Intraoperative diagnostics and elimination of residual microtumours with plasmonic nanobubbles

Precisely Programmable Degradation and Drug Release Profiles in Triblock Copolyether Hydrogels with Cleavable Acetal Pendants

Hydrogels hold significant promise as drug delivery systems due to their distinct advantage of sustained localized drug release. However, the challenge of regulating the initial burst release while achieving precise control over degradation and drug-release kinetics persists. Herein, we present an ABA-type triblock copolymer-based hydrogel system with precisely programmable degradation and release kinetics. The resulting hydrogels were designed with a hydrophilic poly(ethylene oxide) midblock and a hydrophobic end-block composed of polyethers with varying ratios of ethoxyethyl glycidyl ether and tetrahydropyranyl glycidyl ether acetal pendant possessing different hydrolysis kinetics. This unique side-chain strategy enabled us to achieve a broad spectrum of precise degradation and drug-release profiles under mildly acidic conditions while maintaining the cross-linking density and viscoelastic modulus, which is unlike the conventional polyester-based backbone degradation system. Furthermore, programmable degradation of the hydrogels and release of active therapeutic agent paclitaxel loaded therein are demonstrated in an in vivo mouse model by suppressing tumor recurrence following surgical resection. Tuning of the fraction of two acetal pendants in the end-block provided delicate tailoring of hydrogel degradation and the drug release capability to achieve the desired therapeutic efficacy. This study not only affords a facile means to design hydrogels with precisely programmable degradation and release profiles but also highlights the critical importance of aligning the drug release profile with the target disease.

Self-sufficient nanoparticles with dual-enzyme activity trigger radical storms and activate cascade-amplified antitumor immunologic responses

Radiotherapy (RT) can potentially induce systemic immune responses by initiating immunogenic cell death (ICD) of tumor cells. However, RT-induced antitumor immunologic responses are sporadic and insufficient against cancer metastases. Herein, we construct multifunctional self-sufficient nanoparticles (MARS) with dual-enzyme activity (GOx and peroxidase-like) to trigger radical storms and activate the cascade-amplified systemic immune responses to suppress both local tumors and metastatic relapse. In addition to limiting the Warburg effect to actualize starvation therapy, MARS catalyzes glucose to produce hydrogen peroxide (H2O2), which is then used in the Cu+-mediated Fenton-like reaction and RT sensitization. RT and chemodynamic therapy produce reactive oxygen species in the form of radical storms, which have a robust ICD impact on mobilizing the immune system. Thus, when MARS is combined with RT, potent systemic antitumor immunity can be generated by activating antigen-presenting cells, promoting dendritic cells maturation, increasing the infiltration of cytotoxic T lymphocytes, and reprogramming the immunosuppressive tumor microenvironment. Furthermore, the synergistic therapy of RT and MARS effectively suppresses local tumor growth, increases mouse longevity, and results in a 90% reduction in lung metastasis and postoperative recurrence. Overall, we provide a viable approach to treating cancer by inducing radical storms and activating cascade-amplified systemic immunity.

Atomically precise photothermal nanomachines

Interfacing molecular machines to inorganic nanoparticles can, in principle, lead to hybrid nanomachines with extended functions. Here we demonstrate a ligand engineering approach to develop atomically precise hybrid nanomachines by interfacing gold nanoclusters with tetraphenylethylene molecular rotors. When gold nanoclusters are irradiated with near-infrared light, the rotation of surface-decorated tetraphenylethylene moieties actively dissipates the absorbed energy to sustain the photothermal nanomachine with an intact structure and steady efficiency. Solid-state nuclear magnetic resonance and femtosecond transient absorption spectroscopy reveal that the photogenerated hot electrons are rapidly cooled down within picoseconds via electron-phonon coupling in the nanomachine. We find that the nanomachine remains structurally and functionally intact in mammalian cells and in vivo. A single dose of near-infrared irradiation can effectively ablate tumours without recurrence in tumour-bearing mice, which shows promise in the development of nanomachine-based theranostics.

Laser-induced vapor nanobubbles for B16-F10 melanoma cell killing and intracellular delivery of chemotherapeutics

The most lethal form of skin cancer is cutaneous melanoma, a tumor that develops in the melanocytes, which are found in the epidermis. The treatment strategy of melanoma is dependent on the stage of the disease and often requires combined local and systemic treatment. Over the years, systemic treatment of melanoma has been revolutionized and shifted toward immunotherapeutic approaches. Phototherapies like photothermal therapy (PTT) have gained considerable attention in the field, mainly because of their straightforward applicability in melanoma skin cancer, combined with the fact that these strategies are able to induce immunogenic cell death (ICD), linked with a specific antitumor immune response. However, PTT comes with the risk of uncontrolled heating of the surrounding healthy tissue due to heat dissipation. Here, we used pulsed laser irradiation of endogenous melanin-containing melanosomes to induce cell killing of B16-F10 murine melanoma cells in a non-thermal manner. Pulsed laser irradiation of the B16-F10 cells resulted in the formation of water vapor nanobubbles (VNBs) around endogenous melanin-containing melanosomes, causing mechanical cell damage. We demonstrated that laser-induced VNBs are able to kill B16-F10 cells with high spatial resolution. When looking more deeply into the cell death mechanism, we found that a large part of the B16-F10 cells succumbed rapidly after pulsed laser irradiation, reaching maximum cell death already after 4 h. Practically all necrotic cells demonstrated exposure of phosphatidylserine on the plasma membrane and caspase-3/7 activity, indicative of regulated cell death. Furthermore, calreticulin, adenosine triphosphate (ATP) and high-mobility group box 1 (HMGB1), three key damage-associated molecular patterns (DAMPs) in ICD, were found to be exposed from B16-F10 cells upon pulsed laser irradiation to an extent that exceeded or was comparable to the bona fide ICD-inducer, doxorubicin. Finally, we could demonstrate that VNB formation from melanosomes induced plasma membrane permeabilization. This allowed for enhanced intracellular delivery of bleomycin, an ICD-inducing chemotherapeutic, which further boosted cell death with the potential to improve the systemic antitumor immune response.

Injectable Zwitterionic Physical Hydrogel with Enhanced Chemodynamic Therapy and Tumor Microenvironment Remodeling Properties for Synergistic Anticancer Therapy

Surgical resection is the first-line therapy for breast cancer. However, residual tumor cells and the highly immunosuppressive tumor microenvironment (TME) continue to have a serious impact on tumor recurrence and metastasis postresection. Implantation of an in situ hydrogel system postresection has shown to be an effective treatment with great clinical potential. Herein, an injectable zwitterionic hydrogel system was developed for local drug delivery with enhanced immune activation and prevention of tumor recurrence. Driven by electrostatic interactions, poly(sulfobetaine methacrylate) (PSBMA) self-assembles into a hydrogel in saline, achieving low protein adsorption and tunable biodegradability. The chemotherapy drug doxorubicin (DOX) was loaded into copper peroxide nanoparticles (CuO2/DOX), which were coated with macrophage membranes to form tumor-targeting nanoparticles (M/CuO2/DOX). Next, M/CuO2/DOX and the stimulator of interferon genes (STING) agonist 2',3'-cGAMP were coloaded into PSBMA hydrogel (Gel@M/CuO2/DOX/STING). The hydrophilic STING agonist was first released by diffusion from hydrogel to activate the STING pathway and upregulate interferon (IFN) signaling related genes, remodeling the immunosuppressive TME. Then, M/CuO2/DOX targeted the residual tumor cells, combining with DOX-induced DNA damage, immunogenic tumor cell death, and copper death. Hence, this work combines chemodynamic therapy with STING pathway activation in TME, encouraging residual tumor cell death, promoting the maturation of dendritic cells, enhancing tumor-specific CD8+ T cell infiltration, and preventing postoperative recurrence and metastasis.

Thermal Oscillations of Nanobubbles

Nanobubble cavitation is advancing technologies in enhanced wastewater treatment, cancer therapy and diagnosis, and microfluidic cleaning. Current macroscale models predict that nanobubble oscillations should be isothermal, yet recent studies suggest that they are adiabatic with an associated increase in natural frequency, which becomes challenging when characterizing nanobubble sizes using ultrasound in experiments. We derive a new theoretical model that considers the nonideal nature of the nanobubble's internal gas phase and nonequilibrium effects, by employing the van der Waals (vdW) equation of state and implementing a temperature jump term at the liquid-gas interface, respectively, finding excellent agreement with molecular dynamics (MD) simulations. Our results reveal how adiabatic behavior could be erroneously interpreted when analyzing the thermal response of the gas using the commonly employed polytropic process and explain instead how nanobubble oscillations are physically closer to their isothermal limit.

Advances in photoacoustic imaging aided by nano contrast agents: special focus on role of lymphatic system imaging for cancer theranostics

Photoacoustic imaging (PAI) is a successful clinical imaging platform for management of cancer and other health conditions that has seen significant progress in the past decade. However, clinical translation of PAI based methods are still under scrutiny as the imaging quality and clinical information derived from PA images are not on par with other imaging methods. Hence, to improve PAI, exogenous contrast agents, in the form of nanomaterials, are being used to achieve better image with less side effects, lower accumulation, and improved target specificity. Nanomedicine has become inevitable in cancer management, as it contributes at every stage from diagnosis to therapy, surgery, and even in the postoperative care and surveillance for recurrence. Nanocontrast agents for PAI have been developed and are being explored for early and improved cancer diagnosis. The systemic stability and target specificity of the nanomaterials to render its theranostic property depends on various influencing factors such as the administration route and physico-chemical responsiveness. The recent focus in PAI is on targeting the lymphatic system and nodes for cancer diagnosis, as they play a vital role in cancer progression and metastasis. This review aims to discuss the clinical advancements of PAI using nanoparticles as exogenous contrast agents for cancer theranostics with emphasis on PAI of lymphatic system for diagnosis, cancer progression, metastasis, PAI guided tumor resection, and finally PAI guided drug delivery.

Revolutionizing cancer treatment: The power of cell-based drug delivery systems

Intravenous administration of drugs is a widely used cancer therapy approach. However, the efficacy of these drugs is often hindered by various biological barriers, including circulation, accumulation, and penetration, resulting in poor delivery to solid tumors. Recently, cell-based drug delivery platforms have emerged as promising solutions to overcome these limitations. These platforms offer several advantages, including prolonged circulation time, active targeting, controlled release, and excellent biocompatibility. Cell-based delivery systems encompass cell membrane coating, intracellular loading, and extracellular backpacking. These innovative platforms hold the potential to revolutionize cancer diagnosis, monitoring, and treatment, presenting a plethora of opportunities for the advancement and integration of pharmaceuticals, medicine, and materials science. Nevertheless, several technological, ethical, and financial barriers must be addressed to facilitate the translation of these platforms into clinical practice. In this review, we explore the emerging strategies to overcome these challenges, focusing specifically on the functions and advantages of cell-mediated drug delivery in cancer treatment.

Enrichment and sensing tumor cells by embedded immunomodulatory DNA hydrogel to inhibit postoperative tumor recurrence

Postoperative tumor recurrence and metastases often lead to cancer treatment failure. Here, we develop a local embedded photodynamic immunomodulatory DNA hydrogel for early warning and inhibition of postoperative tumor recurrence. The DNA hydrogel contains PDL1 aptamers that capture and enrich in situ relapsed tumor cells, increasing local ATP concentration to provide a timely warning signal. When a positive signal is detected, local laser irradiation is performed to trigger photodynamic therapy to kill captured tumor cells and release tumor-associated antigens (TAA). In addition, reactive oxygen species break DNA strands in the hydrogel to release encoded PDL1 aptamer and CpG, which together with TAA promote sufficient systemic antitumor immunotherapy. In a murine model where tumor cells are injected at the surgical site to mimic tumor recurrence, we find that the hydrogel system enables timely detection of tumor recurrence by enriching relapsed tumor cells to increase local ATP concentrations. As a result, a significant inhibitory effect of approximately 88.1% on recurrent tumors and effectively suppressing metastasis, offering a promising avenue for timely and effective treatment of postoperative tumor recurrence.

Advanced Nitric Oxide Generating Nanomedicine for Therapeutic Applications

Nitric oxide (NO), a gaseous transmitter extensively present in the human body, regulates vascular relaxation, immune response, inflammation, neurotransmission, and other crucial functions. Nitrite donors have been used clinically to treat angina, heart failure, pulmonary hypertension, and erectile dysfunction. Based on NO's vast biological functions, it further can treat tumors, bacteria/biofilms and other infections, wound healing, eye diseases, and osteoporosis. However, delivering NO is challenging due to uncontrolled blood circulation release and a half-life of under five seconds. With advanced biotechnology and the development of nanomedicine, NO donors packaged with multifunctional nanocarriers by physically embedding or chemically conjugating have been reported to show improved therapeutic efficacy and reduced side effects. Herein, we review and discuss recent applications of NO nanomedicines, their therapeutic mechanisms, and the challenges of NO nanomedicines for future scientific studies and clinical applications. As NO enables the inhibition of the replication of DNA and RNA in infectious microbes, including COVID-19 coronaviruses and malaria parasites, we highlight the potential of NO nanomedicines for antipandemic efforts. This review aims to provide deep insights and practical hints into design strategies and applications of NO nanomedicines.

Enhanced Nanobubble Formation: Gold Nanoparticle Conjugation to Qβ Virus-like Particles

Plasmonic gold nanostructures are a prevalent tool in modern hypersensitive analytical techniques such as photoablation, bioimaging, and biosensing. Recent studies have shown that gold nanostructures generate transient nanobubbles through localized heating and have been found in various biomedical applications. However, the current method of plasmonic nanoparticle cavitation events has several disadvantages, specifically including small metal nanostructures (≤10 nm) which lack size control, tuneability, and tissue localization by use of ultrashort pulses (ns, ps) and high-energy lasers which can result in tissue and cellular damage. This research investigates a method to immobilize sub-10 nm AuNPs (3.5 and 5 nm) onto a chemically modified thiol-rich surface of Qβ virus-like particles. These findings demonstrate that the multivalent display of sub-10 nm gold nanoparticles (AuNPs) caused a profound and disproportionate increase in photocavitation by upward of 5-7-fold and significantly lowered the laser fluency by 4-fold when compared to individual sub-10 nm AuNPs. Furthermore, computational modeling showed that the cooling time of QβAuNP scaffolds is significantly extended than that of individual AuNPs, proving greater control of laser fluency and nanobubble generation as seen in the experimental data. Ultimately, these findings showed how QβAuNP composites are more effective at nanobubble generation than current methods of plasmonic nanoparticle cavitation.

A Lysosome-Targeted Near-Infrared Fluorescent Probe with Excellent Water Solubility for Surgery Navigation in Breast Cancer

To get a tumor-targeted contrast agent for imaging guide resection of tumors, we designed a novel fluorescent probe based on the heptamethine cyanine core, Cy7-MO, which has excellent water solubility and near-infrared photophysical and lysosomal targeting properties. The chemical structure of Cy7-MO was characterized by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The toxicity of Cy7-MO was evaluated by cell counting kit-8. Then, a cellular-level study was conducted to evaluate the suborganelle localization in 4T1-Luc1 cells, and it was also used for surgical navigation in orthotopic breast tumor resection in vivo. The results showed that Cy7-MO was well targeted to lysosomes. Importantly, the Cy7-MO probe was found to be well tolerable and exhibited excellent biocompatibility. Moreover, the orthotopic breast tumor margin was clearly visualized through fluorescence guiding of Cy7-MO. Finally, the correct tumor tissues were completely removed, and a negative margin was obtained successfully, which demonstrated an enhanced precision of surgery.

Photothermal Nanomaterial-Mediated Photoporation

ConspectusDelivering biological effector molecules in cultured cells is of fundamental importance to any study or application in which the modulation of gene expression is required. Examples range from generating engineered cell lines for studying gene function to the engineering of cells for cell-based therapies such as CAR-T cells and gene-corrected stem cells for regenerative medicine. It remains a great challenge, however, to deliver biological effector molecules across the cell membrane with minimal adverse effects on cell viability and functionality. While viral vectors have been frequently used to introduce foreign nucleic acids into cells, their use is associated with safety concerns such as immunogenicity, high manufacturing cost, and limited cargo capacity.For photoporation, depending on the laser energy, membrane permeabilization happens either by local heating or by laser-induced water vapor nanobubbles (VNB). In our first study on this topic, we demonstrated that the physical force exerted by suddenly formed VNB leads to more efficient intracellular delivery as compared to mere heating. Next, we explored the use of different photothermal nanomaterials, finding that graphene quantum dots display enhanced thermal stability compared to the more traditionally used gold nanoparticles, hence providing the possibility to increase the delivery efficiency by repeated laser activation. To enable its use for the production of engineered therapeutic cells, it would be better if contact with cells with nondegradable nanoparticles is avoided as it poses toxicity and regulatory concerns. Therefore, we recently demonstrated that photoporation can be performed with biodegradable polydopamine nanoparticles as well. Alternatively, we demonstrated that nanoparticle contact can be avoided by embedding the photothermal nanoparticles in a substrate made from biocompatible electrospun nanofibers. With this variety of photoporation approaches, over the years we demonstrated the successful delivery of a broad variety of biologics (mRNA, siRNA, Cas9 ribonucleoproteins, nanobodies, etc.) in many different cell types, including hard-to-transfect cells such as T cells, embryonic stem cells, neurons, and macrophages.In this Account, we will first start with a brief introduction of the general concept and a historical development of photoporation. In the next two sections, we will extensively discuss the various types of photothermal nanomaterials which have been used for photoporation. We discriminate two types of photothermal nanomaterials: single nanostructures and composite nanostructures. The first one includes examples such as gold nanoparticles, graphene quantum dots, and polydopamine nanoparticles. The second type includes polymeric films and nanofibers containing photothermal nanoparticles as well as composite nanoscale biolistic nanostructures. A thorough discussion will be given for each type of photothermal nanomaterial, from its synthesis and characterization to its application in photoporation, with its advantages and disadvantages. In the final section, we will provide an overall discussion and elaborate on future perspectives.

Reprogramming of tumor-associated macrophages by polyaniline-coated iron oxide nanoparticles applied to treatment of breast cancer

Breast cancer is the most commonly diagnosed type of cancer among the female population worldwide. It is a disease with a high incidence and geographic distribution that negatively impacts global public health and deleteriously affect the quality of life of cancer patients. Among the new approaches, cancer immunotherapy is the most promising trend in oncology by stimulating the host's own immune system to efficiently destroy cancer cells. Recent evidence has indicated that iron oxide nanoparticles can promote the reprograming of M2 into M1 macrophages with anti-tumor effects in the tumor microenvironment. Thus, the aim of the present work was to evaluate the ability of polyaniline-coated maghemite (Pani/γ-Fe₂O₃) nanoparticles to modulate human macrophages in 2D monolayers and 3D multicellular breast cancer models. It was observed that Pani/γ-Fe₂O₃ NPs re-educated IL-10-stimulated macrophages towards a pro-inflammatory profile, decreasing the proportion of CD163⁺ and increasing the CD86⁺ proportion in 2D models. NPs were successfully taken-up by macrophages presented in the 3D model and were also able to induce an increasing in their CD86⁺ proportion in triple MCTs model. Overall, our findings open new perspectives on the use of Pani/γ-Fe₂O₃ NPs as an immunomodulatory therapy for macrophage reprogramming towards an anti-tumor M1 phenotype, providing a new tool for breast cancer immunotherapies.

Nanobubble size distribution measurement by interactive force apparatus under an electric field

Nanobubbles have been applied in many fields, such as environmental cleaning, material production, agriculture, and medicine. However, the measured nanobubble sizes differed among the measurement methods, such as dynamic light scattering, particle trajectory, and resonance mass methods. Additionally, the measurement methods were limited with respect to the bubble concentration, refractive index of liquid, and liquid color. Here, a novel interactive force measurement method for bulk nanobubble size measurement was developed by measuring the force between two electrodes filled with bulk nanobubble-containing liquid under an electric field when the electrode distance was changed in the nm scale with piezoelectric equipment. The nanobubble size was measured with a bubble gas diameter and also an effective water thin film layer covered with a gas bubble that was estimated to be approximately 10 nm based on the difference between the median diameter of the particle trajectory method and this method. This method could also be applied to the solid particle size distribution measurement in a solution.

Nanobubble technologies: Applications in therapy from molecular to cellular level

Nanobubbles are gaseous entities suspended in bulk liquids that have widespread beneficial usage in many industries. Nanobubbles are already proving to be versatile in furthering the effectiveness of disease treatment on cellular and molecular levels. They are functionalized with biocompatible and stealth surfaces to aid in the delivery of drugs. At the same time, nanobubbles serve as imaging agents due to the echogenic properties of the gas core, which can also be utilized for controlled and targeted delivery. This review provides an overview of the biomedical applications of nanobubbles, covering their preparation and characterization methods, discussing where the research is currently focused, and how they will help shape the future of biomedicine.

Engineered drug-loaded cellular membrane nanovesicles for efficient treatment of postsurgical cancer recurrence and metastasis

Cancer recurrence and metastasis are still common causes of postsurgery death in patients with solid tumors, suggesting that additional consolidation therapeutic strategies are necessary. We have previously found that oxaliplatin (OXA) treatment causes further up-regulation of CD155, which is abundantly expressed in tumors for resulting in increased sensitivity of cancer to anti-CD155 therapy. Here, we report O-TPNVs, which are TIGIT-expressing cell membrane and platelet cell membrane fusion nanovesicles (TPNVs) loaded with OXA. Platelet-derived membrane components enable O-TPNVs to target postsurgery wounds and interact with circulating tumor cells (CTCs). OXA directly kills residual tumor cells and CTCs, induces immunogenic cell death, and activates the immune system. TPNVs bind to CD155 on tumor cells, block the CD155/TIGIT pathway, and restore CD8⁺ T cell activity. In vivo analyses reveal that O-TPNVs achieve synergistic chemotherapeutic and immunotherapeutic effects, effectively inhibiting the recurrence and metastasis of triple-negative breast cancer (4T1) after surgery.

Surface-anchored tumor microenvironment-responsive protein nanogel-platelet system for cytosolic delivery of therapeutic protein in the post-surgical cancer treatment

Nanoparticle-anchored platelet systems hold great potential to act as drug carriers in post-surgical cancer treatment due to their intrinsic ability to target the bleeding sites. However, rational design is still needed to further improve its cargo release profiles to meet the cytosolic delivery of therapeutic proteins with intracellular targets. Herein, we developed a tumor microenvironment (TME)-responsive backpack-conjugated platelet system to enhance intracellular protein delivery, thereby significantly inhibiting tumor recurrence after surgery. Specifically, protein nanogels encapsulating GALA and Granzyme B (GrB) are conjugated on the platelet surface via an acid-sensitive benzoic-imine linker through a biorthogonal reaction (GALA-GNGs-P). Taking advantage of wound-tropism of platelets, GALA-GNGs-P could actively accumulate at the surgical trauma and release nanogels in response to acidic TME for promoting deep penetration. Following cellular uptake, the pore-forming peptide GALA helps nanogels escape from lysosome. Subsequently, high glutathione (GSH) concentration in tumor cytoplasm facilitates GrB release from NGs, leading to intense cell apoptosis. GALA-GNGs-P shows remarkable tumor-targeting capability, high cellular uptake, and outstanding lysosomal escaping ability, which can significantly inhibit tumor recurrence in mice models with incomplete tumor resection. Our findings indicate that platelets bioengineered with TME-responsive protein nanogels provide an option to intracellularly deliver therapeutic proteins for the post-surgical treatment of cancer. STATEMENT OF SIGNIFICANCE: Platelet-based drug delivery systems (DDSs) have gained considerable achievements in post-surgical cancer treatment. However, there is no research exploring their potential in realizing the controllable release of cargoes in the acidic tumor microenvironment (TME). Herein, we developed a TME-responsive bioengineered platelet delivery platform (GALA-GNGs-P) for achieving controllable and effective protein intracellular delivery to overcome post-surgical tumor recurrence. Our surface-anchored nanogel-platelet system has the following advantages: (i) improving the loading efficiency of therapeutic proteins, (ii) affecting no physiological function of platelets, (iii) realizing on-demand cargo release in the acidic TME, and (iv) helping proteins escape from endosomal entrapment. Our findings further explored the prospect of cellular backpack system and realized the controllable release of cargoes in the acidic TME.

Direct measuring of single-heterogeneous bubble nucleation mediated by surface topology

Heterogeneous bubble nucleation is one of the most fundamental interfacial processes ranging from nature to technology. There is excellent evidence that surface topology is important in directing heterogeneous nucleation; however, deep understanding of the energetics by which nanoscale architectures promote nucleation is still challenging. Herein, we report a direct and quantitative measurement of single-bubble nucleation on a single silica nanoparticle within a microsized droplet using scanning electrochemical cell microscopy. Local gas concentration at nucleation is determined from finite element simulation at the corresponding faradaic current of the peak-featured voltammogram. It is demonstrated that the criteria gas concentration for nucleation first drops and then rises with increasing nanoparticle radius. An optimum nanoparticle radius around 10 nm prominently expedites the nucleation by facilitating the special topological nanoconfinements that consequently catalyze the nucleation. Moreover, the experimental result is corroborated by our theoretical calculations of free energy change based on the classic nucleation theory. This study offers insights into the impact of surface topology on heterogenous nucleation that have not been previously observed.

Enhanced postoperative cancer therapy by iron-based hydrogels

Surgical resection is a widely used method for the treatment of solid tumor cancers. However, the inhibition of tumor recurrence and metastasis are the main challenges of postoperative tumor therapy. Traditional intravenous or oral administration have poor chemotherapeutics bioavailability and undesirable systemic toxicity. Polymeric hydrogels with a three-dimensional network structure enable on-site delivery and controlled release of therapeutic drugs with reduced systemic toxicity and have been widely developed for postoperative adjuvant tumor therapy. Among them, because of the simple synthesis, good biocompatibility, biodegradability, injectability, and multifunctionality, iron-based hydrogels have received extensive attention. This review has summarized the general synthesis methods and construction principles of iron-based hydrogels, highlighted the latest progress of iron-based hydrogels in postoperative tumor therapy, including chemotherapy, photothermal therapy, photodynamic therapy, chemo-dynamic therapy, and magnetothermal-chemical combined therapy, etc. In addition, the challenges towards clinical application of iron-based hydrogels have also been discussed. This review is expected to show researchers broad perspectives of novel postoperative tumor therapy strategy and provide new ideas in the design and application of novel iron-based hydrogels to advance this sub field in cancer nanomedicine.

Pulsed Laser Excited Photoacoustic Effect for Disease Diagnosis and Therapy

Pulsed laser can excite light absorber to generate photoacoustic (PA) effect, that is, when the absorber is irradiated with pulsed laser, the absorbed light energy is converted into local heat to cause rapid thermoelastic expansion and generate acoustic wave. The generated PA signal has been widely employed for the diagnosis of many diseases with superb contrast, high penetrability and sensitivity. In addition, with the increase of pulsed laser energy, the resulting PA shockwave and cavitation can promote efficient drug release at lesion sites to potentiate the resulting therapeutic efficacy. Furthermore, the PA shockwave/cavitation can mechanically inhibit disease and produce reactive species. In this Concept article, the principle and research status of pulsed laser excited disease theranostics are briefly summarized, extra suggestions are proposed to inspire extensive PA probes and photodynamic materials as well as novel methodologies.

Bioengineered Platelets Combining Chemotherapy and Immunotherapy for Postsurgical Melanoma Treatment: Internal Core-Loaded Doxorubicin and External Surface-Anchored Anti-PD-L1 Antibody Backpacks

The pivotal factors affecting the survival rate of patients include metastasis and tumor recurrence after the resection of the primary tumor. Anti-PD-L1 antibody (aPD-L1) has promising efficacy but with some side effects for the off-target binding between aPD-L1 and normal tissues. Here, inspired by the excellent targeting capability of platelets with respect to tumor cells, we propose bioengineered platelets (PDNGs) with inner-loaded doxorubicin (DOX) and outer-anchored aPD-L1-cross-linked nanogels to reduce tumor relapse and metastatic spread postoperation. The cargo does not impair the normal physiological functions of platelets. Free aPD-L1 is cross-linked to form nanogels with a higher drug-loading efficiency and is sustainably released to trigger the T-cell-mediated destruction of tumor cells, reversing the tumor immunosuppressive microenvironment. PDNGs can reduce the postoperative tumor recurrence and metastasis rate, prolonging the survival time of mice. Our findings indicate that bioengineered platelets are promising in postsurgical cancer treatment by the tumor-capturing and in situ microvesicle-secreting capabilities of platelets.

Digital plasmonic nanobubble detection for rapid and ultrasensitive virus diagnostics

Rapid and sensitive diagnostics of infectious diseases is an urgent and unmet need as evidenced by the COVID-19 pandemic. Here, we report a strategy, based on DIgitAl plasMONic nanobubble Detection (DIAMOND), to address this need. Plasmonic nanobubbles are transient vapor bubbles generated by laser heating of plasmonic nanoparticles (NPs) and allow single-NP detection. Using gold NPs as labels and an optofluidic setup, we demonstrate that DIAMOND achieves compartment-free digital counting and works on homogeneous immunoassays without separation and amplification steps. DIAMOND allows specific detection of respiratory syncytial virus spiked in nasal swab samples and achieves a detection limit of ~100 PFU/mL (equivalent to 1 RNA copy/µL), which is competitive with digital isothermal amplification for virus detection. Therefore, DIAMOND has the advantages including one-step and single-NP detection, direct sensing of intact viruses at room temperature, and no complex liquid handling, and is a platform technology for rapid and ultrasensitive diagnostics.

Multifunctional Flavonoid-Silica Nanohydrogel Enables Simultaneous Inhibition of Tumor Recurrence and Bacterial Infection in Post-Surgical Treatment

A strategy to synthesize water-soluble and fluorescent flavonoid-silica nanocomposites (FSiNCs) simultaneously featuring anti-tumor and anti-bacterial abilities is developed. Furthermore, it is demonstrated that the therapeutic effects of FSiNCs are associated with the selective accumulation of reactive oxide species in both tumor and bacteria cells. Following that, the resultant FSiNCs are incorporated with thrombin and fibrinogen, being sprayed onto the tumor surgical wound site to in situ form fibrin gel (FSiNCs@Fibrin). Remarkably, such FSiNCs@Fibrin results in an ≈18-fold reduction in intratumoral bacteria numbers and ≈12-fold decrease in tumor regrowth compared to equivalent free flavonoid-loaded gel.

Targeted Inhibition of Tumor Inflammation and Tumor-Platelet Crosstalk by Nanoparticle-Mediated Drug Delivery Mitigates Cancer Metastasis

Sowing malignant cells (the "seeds" of metastasis) to engraft secondary sites requires a conducive premetastatic niche (PMN, the "soil" of metastasis). Inflammation and tumor associated platelet (TAP) has been hijacked by primary tumors to induce PMN "soil" in distant organs, as well as facilitate the dissemination of "seeds". This study reports a combinatory strategy with activated platelet-targeting nanoparticles to aim at the dynamic process of entire cancer metastasis, which exerts robust antimetastasis efficacy by simultaneously inhibiting tumor inflammation and tumor-platelet crosstalk. Our results reveals that the PSN peptide (a P-selectin-targeting peptide) modification enriched the accumulation of nanoparticles in primary tumor, pulmonary PMN, and metastases via capturing activated platelet. Such characteristics contribute to the efficient inhibition on almost every crucial and consecutive step of the metastasis cascade by retarding epithelial-mesenchymal transition (EMT) progression within tumors, specifically blocking the tumor-platelet crosstalk to remove the platelets "protective shield" around disseminated "seeds", and reversing the inflammatory microenvironment to interfere with the "soil" formation. Consisting of inflammation inhibiting and TAP impeding nanoparticles, this approach prominently reduces various metastasis in abscopal lung, including spontaneous metastasis, disseminated tumor cells metastasis, and post-operative metastasis. This work provides a generalizable nanoplatform of parallel inflammation disturbance and tumor-TAP crosstalk blockade to resist metastatic tumors.

Nanomaterials with changeable physicochemical property for boosting cancer immunotherapy

The past decade has witnessed a great progress in cancer immunotherapy with the sequential approvals of therapeutic cancer vaccine, immune checkpoint inhibitor and chimeric antigen receptor (CAR) T cell therapy. However, some hurdles still remain to the wide implementation of cancer immunotherapy, including low immune response, complex tumor heterogeneity, off-target immunotoxicity, poor solid tumor infiltration, and immune evasion-induced treatment tolerance. Owing to changeable physicochemical properties in response to endogenous or exogenous stimuli, nanomaterials hold the remarkable potential in incorporation of multiple agents, efficient biological barrier penetration, precise immunomodulator delivery, and controllable content release for boosting cancer immunotherapy. Herein, we review the recent advances in nanomaterials with changeable physicochemical property (NCPP) to develop cancer vaccine, remold tumor microenvironment and evoke direct T cell activation. Besides, we provide our outlook on this emerging field at the intersection of NCPP design and cancer immunotherapy.

Do Lipid-based Nanoparticles Hold Promise for Advancing the Clinical Translation of Anticancer Alkaloids?

Since the commercialization of morphine in 1826, numerous alkaloids have been isolated and exploited effectively for the betterment of mankind, including cancer treatment. However, the commercialization of alkaloids as anticancer agents has generally been limited by serious side effects due to their lack of specificity to cancer cells, indiscriminate tissue distribution and toxic formulation excipients. Lipid-based nanoparticles represent the most effective drug delivery system concerning clinical translation owing to their unique, appealing characteristics for drug delivery. To the extent of our knowledge, this is the first review to compile in vitro and in vivo evidence of encapsulating anticancer alkaloids in lipid-based nanoparticles. Alkaloids encapsulated in lipid-based nanoparticles have generally displayed enhanced in vitro cytotoxicity and an improved in vivo efficacy and toxicity profile than free alkaloids in various cancers. Encapsulated alkaloids also demonstrated the ability to overcome multidrug resistance in vitro and in vivo. These findings support the broad application of lipid-based nanoparticles to encapsulate anticancer alkaloids and facilitate their clinical translation. The review then discusses several limitations of the studies analyzed, particularly the discrepancies in reporting the pharmacokinetics, biodistribution and toxicity data. Finally, we conclude with examples of clinically successful encapsulated alkaloids that have received regulatory approval and are undergoing clinical evaluation.

Portable air-fed cold atmospheric plasma device for postsurgical cancer treatment

Surgery represents the major option for treating most solid tumors. Despite continuous improvements in surgical techniques, cancer recurrence after surgical resection remains the most common cause of treatment failure. Here, we report cold atmospheric plasma (CAP)–mediated postsurgical cancer treatment, using a portable air-fed CAP (aCAP) device. The aCAP device we developed uses the local ambient air as the source gas to generate cold plasma discharge with only joule energy level electrical input, thus providing a device that is simple and highly tunable for a wide range of biomedical applications. We demonstrate that local aCAP treatment on residual tumor cells at the surgical cavities effectively induces cancer immunogenic cell death in situ and evokes strong T cell–mediated immune responses to combat the residual tumor cells. In both 4T1 breast tumor and B16F10 melanoma models, aCAP treatment after incomplete tumor resection contributes to inhibiting tumor growth and prolonging survival.

Inhibition of post-surgery tumour recurrence via a hydrogel releasing CAR-T cells and anti-PDL1-conjugated platelets

The immunosuppressive microenvironment of solid tumours reduces the antitumour activity of chimeric antigen receptor T cells (CAR-T cells). Here, we show that the release-through the implantation of a hyaluronic acid hydrogel-of CAR-T cells targeting the human chondroitin sulfate proteoglycan 4, polymer nanoparticles encapsulating the cytokine interleukin-15 and platelets conjugated with the checkpoint inhibitor programmed death-ligand 1 into the tumour cavity of mice with a resected subcutaneous melanoma tumour inhibits the local recurrence of the tumour as well as the growth of distant tumours, through the abscopal effect. The hydrogel, which functions as a reservoir, facilitates the enhanced distribution of the CAR-T cells within the surgical bed, and the inflammatory microenvironment triggers platelet activation and the subsequent release of platelet-derived microparticles. The post-surgery local delivery of combination immunotherapy through a biocompatible hydrogel reservoir could represent a translational route for preventing the recurrence of cancers with resectable tumours.

Single 808 nm near-infrared-triggered multifunctional upconverting phototheranostic nanocomposite for imaging-guided high-efficiency treatment of tumors

Multifunctional phototheranostic nanocomposites are promising for early diagnosis and precision therapy of cancer. Aim to enhance their accuracy and efficiency, in this study, we develop a single-laser excited activatable phototheranostic nanocomposite (UCNPs-D-MQ): 808 nm-excited upconverting nanoparticles (UCNPs) as the matrix programmed assembly with amphipathic compound DSPE-PEG-COOH, a near-infrared absorbing polymer DPP and the pro-photosensitizer MBQB. Upon endocytosed by cancer cells and excited by the 808 nm laser, UCNPs-D-MQ could produce high-yield reactive oxygen species (ROS) as the results of singlet oxygen generation from transferring to methylene blue, GSH depletion and ROS generation from photoactivation. It was proven both in vitro and in vivo that the nanocomposites exhibits remarkable therapeutic efficacy as well as minimal photodamage to normal cells. These results reveal UCNPs-D-MQ as a robust theranostic agent for tumor phototherapy.

Boosting Photoacoustic Effect via Intramolecular Motions Amplifying Thermal-to-Acoustic Conversion Efficiency for Adaptive Image-Guided Cancer Surgery

Photoacoustic (PA) imaging emerges as a promising technique for biomedical applications. The development of new strategies to boost PA conversion without depressing other properties (e.g., fluorescence) is highly desirable for multifunctional imaging but difficult to realize. Here, we report a new phenomenon that active intramolecular motions could promote PA signal by specifically increasing thermal-to-acoustic conversion efficiency. The compound with intense intramolecular motion exhibits amplified PA signal by elevating thermal-to-acoustic conversion, and the fluorescence also increases due to aggregation-induced emission signature. The simultaneously high PA and fluorescence brightness of TPA-TQ3 NPs enable precise image-guided surgery. The preoperative fluorescence and PA imaging are capable of locating orthotopic breast tumor in a high-contrast manner, and the intraoperative fluorescence imaging delineates tiny residual tumors. This study highlights a new design guideline of intramolecular motion amplifying PA effect.

Stimuli-responsive nanobubbles for biomedical applications

Stimuli-responsive nanobubbles have received increased attention for their application in spatial and temporal resolution of diagnostic techniques and therapies, particularly in multiple imaging methods, and they thus have significant potential for applications in the field of biomedicine. This review presents an overview of the recent advances in the development of stimuli-responsive nanobubbles and their novel applications. Properties of both internal- and external-stimuli responsive nanobubbles are highlighted and discussed considering the potential features required for biomedical applications. Furthermore, the methods used for synthesis and characterization of nanobubbles are outlined. Finally, novel biomedical applications are proposed alongside the advantages and shortcomings inherent to stimuli-responsive nanobubbles.

Delivery of Foreign Materials into Adherent Cells by Gold Nanoparticle-Mediated Photoporation

Delivering extracellular materials into adherent cells presents several challenges. A homemade photoporation platform, mediated by gold nanoparticles (AuNPs), was constructed to find a suitable method for finding all adherent cells in this process with high delivery efficiency. The thermal dynamics of AuNPs could be monitored. Based on this system, 60 nm AuNPs were selected to be attached to cells for optimal photoporation. After irradiating the cells covered with AuNPs using a nanosecond pulse laser, fluorescein isothiocyanate-dextran in the medium were delivered into optoporated adherent HeLa (human cervical cell lines) cells. The delivery efficiency and cell viability of this process were evaluated using a fluorescence microscope and flow cytometry. The experimental results showed that targeting cells using antibodies, laser irradiation from the top of the cell culture well, and reducing the cell medium are important for improving the delivery efficiency. The optimal loading efficiency for adherent HeLa cells was 53.4%.

Shock-induced collapse of surface nanobubbles

The collapse of cavitation bubbles often releases high-speed liquid jets capable of surface damage, with applications in drug delivery, cancer treatment, and surface cleaning. Spherical cap-shaped surface nanobubbles have previously been found to exist on immersed substrates. Despite being known nucleation sites for cavitation, their collapsing dynamics are currently unexplored. Here, we use molecular dynamics simulations to model the shock-induced collapse of different surface nanobubble sizes and contact angles. Comparisons are made with additional collapsing spherical nanobubble simulations near a substrate, to investigate the differences in their jet formation and resulting substrate pitting damage. Our main finding is that the pitting damage in the surface nanobubble simulations is greatly reduced, when compared to the spherical nanobubbles, which is primarily caused by the weaker jets formed during their collapse. Furthermore, the pit depths for surface nanobubble collapse do not depend on bubble size, unlike in the spherical nanobubble cases, but instead depend only on their contact angle. We also find a linear scaling relationship for all bubble cases between the final substrate damage and the peak pressure impulse at the impact centre, which can now be exploited to assess the relative damage in other computational studies of collapsing bubbles. We anticipate the more controlled surface-damage features produced by surface nanobubble cavitation jets will open up new applications in advanced manufacturing, medicine, and precision cleaning.

Bubble Forming Films for Spatial Selective Cell Killing

Photodynamic and photothermal cell killing at the surface of tissues finds applications in medicine. However, a lack of control over heat dissipation following a treatment with light might damage surrounding tissues. A new strategy to kill cells at the surface of tissues is reported. Polymeric films are designed in which iron oxide nanoparticles are embedded as photosensitizers. Irradiation of the films with pulsed laser light generates water vapor bubbles at the surface of the films. It is found that "bubble-films" can kill cells in close proximity to the films due to mechanical forces which arise when the bubbles collapse. Local irradiation of bubble-films allows for spatial selective single cell killing. As nanosurgery becomes attractive in ophthalmology to remove superficial tumors, bubble-films are applied on the cornea and it is found that irradiation of the bubble-films allows spatial and selective killing of corneal cells. As i) the photosensitizer is embedded in the films, which reduces its uptake by cells and spreading into tissues and ii) the bubble-films can be removed from the tissue after laser treatment, while iii) a low laser fluence is sufficient to generate vapor bubbles, it is foreseen that bubble-films might become promising for safe resection of superficial tumors.

Engineering biocompatible TeSex nano-alloys as a versatile theranostic nanoplatform

Photothermal nanotheranostics, especially in the near infrared II (NIR-II) region, exhibits a great potential in precision and personalized medicine, owing to high tissue penetration of NIR-II light. The NIR-II-photothermal nanoplatforms with high biocompatibility as well as high photothermal effect are urgently needed but rarely reported so far. Te nanomaterials possess high absorbance to NIR-II light but also exhibit high cytotoxicity, impeding their biomedical applications. In this work, the controllable incorporation of biocompatible Se into the lattice of Te nanostructures is proposed to intrinsically tune their inherent cytotoxicity and enhance their biocompatibility, developing TeSex nano-alloys as a new kind of theranostic nanoplatforms. We have uncovered that the cytotoxicity of Te nanomaterials primarily derives from irreversible oxidation stress and intracellular imbalance of organization and energy, and can be eliminated by incorporating a moderate proportion of Se (x=0.43). We have also discovered that the as-prepared TeSex nano-alloys have extraordinarily high NIR-II-photothermal conversion efficiency (77.2%), 64Cu coordination and computed tomography (CT) contrast capabilities, enabling high-efficacy multimodal photothermal/photoacoustic/positron emission tomography (PET)/CT imaging-guided NIR-II-photothermal therapy of cancer. The proposed nano-alloying strategy provides a new route to improve the biocompatibility of biomedical nanoplatforms and endow them with versatile theranostic functions.

The reversal of chemotherapy-induced multidrug resistance by nanomedicine for cancer therapy

Multidrug resistance (MDR) of cancer is a persistent problem in chemotherapy. Scientists have considered the overexpressed efflux transporters responsible for MDR and chemotherapy failure. MDR extremely limits the therapeutic effect of chemotherapy in cancer treatment. Many strategies have been applied to solve this problem. Multifunctional nanoparticles may be one of the most promising approaches to reverse MDR of tumor. These nanoparticles can keep stability in the blood circulation and selectively accumulated in the tumor microenvironment (TME) either by passive or active targeting. The stimuli-sensitive or organelle-targeting nanoparticles can release the drug at the targeted-site without exposure to normal tissues. In order to better understand reversal of MDR, three main strategies are concluded in this review. First strategy is the synergistic effect of chemotherapeutic drugs and ABC transporter inhibitors. Through directly inhibiting overexpressed ABC transporters, chemotherapeutic drugs can enter into resistant cells without being efflux. Second strategy is based on nanoparticles circumventing over-expressed efflux transporters and directly targeting resistance-related organelles. Third approach is the combination of multiple therapy modes overcoming cancer resistance. At last, numerous researches demonstrated cancer stem-like cells (CSCs) had a deep relation with drug resistance. Here, we discuss two different drug delivery approaches of nanomedicine based on CSC therapy.

Microfluidic Generation of Monodisperse Nanobubbles by Selective Gas Dissolution

Nanotechnology currently enables the fabrication of uniform solid nanoparticles and liquid nano-emulsions, but not uniform gaseous nanobubbles (NBs). In this article, for the first time, a method based on microfluidics that directly produces monodisperse NBs is reported. Specifically, a two-component gas mixture of water-soluble nitrogen and water-insoluble octafluoropropane as the gas phase are used in a microfluidic bubble generator. First, monodisperse microbubbles (MBs) with a classical microfluidic flow-focusing junction is generated, then the MBs shrink down to ≈100 nm diameter, due to the dissolution of the water-soluble components in the gas mixture. The degree of shrinkage is controlled by tuning the ratio of water-soluble to water-insoluble gas components. This technique maintains the monodispersity of the NBs, and enables precise control of the final NB size. It is found that the monodisperse NBs show better homogeneity than polydisperse NBs in in vitro ultrasound imaging experiments. Proof-of-concept in vivo kidney imaging is performed in live mice, demonstrating enhanced contrast using the monodisperse NBs. The NB monodispersity and imaging results make microfluidically generated NBs promising candidates as ultrasound contrast and molecular imaging agents.

Real-Time Intraoperative Surface-Enhanced Raman Spectroscopy-Guided Thermosurgical Eradication of Residual Microtumors in Orthotopic Breast Cancer

Residual microtumors following surgical resection are the major cause for lethal cancer recurrence. However, it remains challenging to completely eliminate these residual microtumors. Here, we report an integrated strategy for image-guided surgical resection of tumors and intraoperative surface-enhanced Raman spectroscopy (SERS) guided thermosurgical elimination of residual microtumors using a "three-in-one" theranostic nanoprobe, termed the Au nanostar-based photoacoustic (PA), SERS, and thermosurgical (starPART) probe. This starPART probe, comprising an Au nanostar core, a Raman molecule layer, and a silica outer layer, draws upon the significant advantages of PA imaging, SERS detection, and photothermal tumor ablation. These prominent features enable preoperative PA imaging for surgical resection of tumors and intraoperative SERS-guided thermosurgery for complete elimination of residual microtumors. In vivo experiments confirm complete eradication of microtumors without local recurrence and with a 100% tumor-free survivability. This work therefore offers a robust platform for real-time intraoperative eradication of residual microtumors with significant improvement of surgical outcomes.

Ultrasound lighting up AIEgens for potential surgical navigation

Multifunctional contrast-enhanced agents suitable for application in surgical navigation by taking advantage of the merits of their diverse imaging modalities at different surgical stages are highly sought-after. Herein, an amphipathic polymer composed of aggregation-induced emission fluorogens (AIEgens) and Gd³⁺ chelates was successfully synthesized and assembled into ultrasound responsive microbubbles (AIE-Gd MBs) to realize potential tri-modal contrast-enhanced ultrasound (US) imaging, magnetic resonance imaging (MRI), and AIEgen-based fluorescence imaging (FI) during the perioperative period. Through ultrasound targeted microbubble destruction (UTMD) and cavitation effect, the as-prepared AIE-Gd MBs went through a MBs-to-nanoparticles (NPs) conversion, which not only resulted in targeted accumulation in tumor tissues but also led to stronger fluorescence being exhibited due to the more aggregated AIE-Gd molecules in the NPs. As a proof-of-concept, our work proposes a strategy of US-lit-up AIEgens in tumors which could offer a simple and powerful tool for surgical navigation in the future.

Single-Particle Counting Based on Digital Plasmonic Nanobubble Detection for Rapid and Ultrasensitive Diagnostics

Rapid and sensitive diagnostics of infectious diseases is an urgent and unmet need as evidenced by the COVID-19 pandemic. Here we report a novel strategy, based on DIgitAl plasMONic nanobubble Detection (DIAMOND), to address these gaps. Plasmonic nanobubbles are transient vapor bubbles generated by laser heating of plasmonic nanoparticles and allow single-particle detection. Using gold nanoparticles labels and an optofluidic setup, we demonstrate that DIAMOND achieves a compartment-free digital counting and works on homogeneous assays without separation and amplification steps. When applied to the respiratory syncytial virus diagnostics, DIAMOND is 150 times more sensitive than commercial lateral flow assays and completes measurements within 2 minutes. Our method opens new possibilities to develop single-particle digital detection methods and facilitate rapid and ultrasensitive diagnostics.

One Sentence Summary

Single-particle digital plasmonic nanobubble detection allows rapid and ultrasensitive detection of viruses in a one-step homogeneous assay.

Antifouling Dendrimer-Entrapped Copper Sulfide Nanoparticles Enable Photoacoustic Imaging-Guided Targeted Combination Therapy of Tumors and Tumor Metastasis

The development of functional intelligent theranostic nanoplatform for imaging-directed synchronous inhibition of primary tumor and tumor metastasis is still a challenging task. We present here the creation of functional dendrimer-entrapped CuS nanoparticles (CuS DENPs) complexed with plasmid DNA-encoding hypermethylation in cancer 1 (pDNA-HIC1) for photoacoustic (PA) imaging-directed simultaneous inhibition of tumors and tumor metastasis. Poly(amidoamine) dendrimers of generation 5 were covalently attached with 1,3-propane sultone and arginine-glycine-aspartic acid (RGD) peptide through a spacer of poly(ethylene glycol) and adopted for the templated synthesis of CuS NPs. The prepared functional RGD-CuS DENPs possess a mean CuS core diameter of 4.2 nm, good colloidal stability, and an excellent absorption feature in the second near-infrared window, thus having a photothermal conversion efficiency of 49.8% and an outstanding PA imaging capability. The functional DENPs can effectively deliver pDNA-HIC1 to prevent cancer cell invasion and metastasis in a serum-enhancing manner by virtue of zwitterionic modification-rendered antifouling property. The developed RGD-CuS DENPs/pDNA polyplexes display α_vβ₃ integrin-targeted enhanced anticancer activity through the combined CuS NP-mediated photothermal therapy (PTT) and pDNA delivery-rendered cancer cell metastasis inhibition. This can also be proven by the therapeutic efficacy of a triple-negative breast cancer model in vivo, where inhibition of both the primary subcutaneous tumor and lung metastasis can be realized. The created dendrimer-CuS hybrid nanoplatform represents one of the updated designs of nanomedicine for PA imaging-directed combination PTT/gene therapy of tumors and tumor metastasis.

Near-infrared small molecule coupled with rigidness and flexibility for high-performance multimodal imaging-guided photodynamic and photothermal synergistic therapy

Photodynamic therapy (PDT) synergized photothermal therapy (PTT) shows superior clinical application prospects than single PDT or PTT. On the other hand, multimodal imaging can delineate comprehensive information about the lesion site and thus help to improve therapy accuracy. However, integrating all these functions into one single molecule is challenging, let alone balancing and maximizing the efficacy of each function. Herein, a near-infrared (NIR) small molecule (ETTC) with an "acceptor-donor-acceptor" structure was designed and synthesized by coupling rigity and flexibility to simultaneously achieve NIR-II fluorescence imaging (NIR-II FLI), photoacoustic imaging, PTT and PDT. The efficacy of each functionality was well balanced and optimized (NIR-II quantum yield: 3.0%; reactive oxygen species generation: 3.2-fold higher than ICG; photothermal conversion efficiency: 52.8%), which may be attributed to the coupling of the rigid and flexible structures in ETTC to tactically manipulate the energy dissipation paths (non-radiative against radiative decay). As a proof-of-concept, under the effective guidance of local-tumor imaging by PA and whole-body imaging by NIR-II FL, complete tumor eradication was achieved via PDT and PTT combinational therapy. This work provides a novel perspective into conceiving and developing single molecule for efficient versatile biomedical applications.

Photoacoustic Cavitation-Ignited Reactive Oxygen Species to Amplify Peroxynitrite Burst by Photosensitization-Free Polymeric Nanocapsules

Photoacoustic (PA) technology can transform light energy into acoustic wave, which can be used for either imaging or therapy that depends on the power density of pulsed laser. Here, we report photosensitizer-free polymeric nanocapsules loaded with nitric oxide (NO) donors, namely NO-NCPs, formulated from NIR light-absorbable amphiphilic polymers and a NO-releasing donor, DETA NONOate. Controlled NO release and nanocapsule dissociation are achieved in acidic lysosomes of cancer cells. More importantly, upon pulsed laser irradiation, the PA cavitation can excite water to generate significant reactive oxygen species (ROS) such as superoxide radical (O₂ ^.- ), which further spontaneously reacts with the in situ released NO to burst highly cytotoxic peroxynitrite (ONOO^- ) in cancer cells. The resultant ONOO^- generation greatly promotes mitochondrial damage and DNA fragmentation to initiate programmed cancer cell death. Apart from PA imaging, PA cavitation can intrinsically amplify reactive species via photosensitization-free materials for promising disease theranostics.

Cell-Membrane-Display Nanotechnology

Advances in material science have set the stage for nanoparticle-based research with potent applications for the diagnosis, bioimaging, and precise treatment of diseases. Despite the wide range of biomaterials developed, the rational design of biomaterials with predictable bioactivity and safety remains a critical challenge. In recent years, the field of cell-membrane-based therapeutics has emerged as a promising platform for addressing unmet medical needs. The utilization of natural cell membranes endows biomaterials with a remarkable ability to serve as biointerfaces that interact with the host environment. To improve the function and efficacy of cell-membrane-based therapeutics, a series of novel strategies is developed as cell-membrane-display nanotechnology, which utilizes various methods to selectively display therapeutic molecules of cell membranes on nanoparticles. Although cell-membrane-display nanotechnology remains in the early phases, considerable work is currently being conducted in the field. This review discusses details of innovative strategies for displaying cell-membrane molecules, including the following: 1) displaying molecules of cell membranes on biomaterials, 2) pretreating cell membranes to induce increased expression of inherent molecules of cell membranes and enhance their function, and 3) inserting additional functional molecules on cell membranes. For each area, the theoretical basis, application scenarios, and potential development are highlighted.

Gold nanoparticle-mediated bubbles in cancer nanotechnology

Microbubbles (MBs) have been extensively investigated in the field of biomedicine for the past few decades. Ultrasound and laser are the most frequently used sources of energy to produce MBs. Traditional acoustic methods induce MBs with poor localized areas of action. A high energy level is required to generate MBs through the focused continuous laser, which can be harmful to healthy tissues. As an alternative, plasmonic light-responsive nanoparticles, such as gold nanoparticles (AuNPs), are preferably used with continuous laser to decrease the energy threshold and reduce the bubbles area of action. It is also well-known that the utilization of the pulsed lasers instead of the continuous lasers decreases the needed AuNPs doses as well as laser power threshold. When well-confined bubbles are generated in biological environments, they play their own unique mechanical and optical roles. The collapse of a bubble can mechanically affect its surrounding area. Such a capability can be used for cargo delivery to cancer cells and cell surgery, destruction, and transfection. Moreover, the excellent ability of light scattering makes the bubbles suitable for cancer imaging. This review firstly provides an overview of the fundamental aspects of AuNPs-mediated bubbles and then their emerging applications in the field of cancer nanotechnology will be reviewed. Although the pre-clinical studies on the AuNP-mediated bubbles have shown promising data, it seems that this technique would not be applicable to every kind of cancer. The clinical application of this technique may basically be limited to the good accessible lesions like the superficial, intracavity and intraluminal tumors. The other essential challenges against the clinical translation of AuNP-mediated bubbles are also discussed.

Forced oscillation dynamics of surface nanobubbles

Surface nanobubbles have potential applications in the manipulation of nanoscale and biological materials, waste-water treatment, and surface cleaning. These spherically capped bubbles of gas can exist in stable diffusive equilibrium on chemically patterned or rough hydrophobic surfaces, under supersaturated conditions. Previous studies have investigated their long-term response to pressure variations, which is governed by the surrounding liquid's local supersaturation; however, not much is known about their short-term response to rapid pressure changes, i.e., their cavitation dynamics. Here, we present molecular dynamics simulations of a surface nanobubble subjected to an external oscillating pressure field. The surface nanobubble is found to oscillate with a pinned contact line, while still retaining a mostly spherical cap shape. The amplitude-frequency response is typical of an underdamped system, with a peak amplitude near the estimated natural frequency, despite the strong viscous effects at the nanoscale. This peak is enhanced by the surface nanobubble's high internal gas pressure, a result of the Laplace pressure. We find that accurately capturing the gas pressure, bubble volume, and pinned growth mode is important for estimating the natural frequency, and we propose a simple model for the surface nanobubble frequency response, with comparisons made to other common models for a spherical bubble, a constant contact angle surface bubble, and a bubble entrapped within a cylindrical micropore. This work reveals the initial stages of growth of cavitation nanobubbles on surfaces, common in heterogeneous nucleation, where classical models based on spherical bubble growth break down.