Multifunctional biocompatible chitosan-polypyrrole nanocomposites as novel agents for photoacoustic imaging-guided photothermal ablation of cancer

Leveraging Non-Radiative Transitions in Asphaltenes-Derived Carbon Dots for Cancer Photothermal Therapy

Cancer photothermal therapy leverages the capability of photothermal agents to convert light to heat for cancer cell ablation and necrosis. However, most conventional photothermal agents (Au, CuS, Pd, mesoporous silica nanoparticles, and indocyanine green dye) either face scalability challenges or photobleached upon prolonged irradiation which jeopardizes practical applications. Here, asphaltenes-derived carbon dots (ACDs, 5 nm) are rationally engineered as a low-cost and photostable photothermal agent with negligible in vivo cytotoxicity. The abundant water-solvating functional groups on the ACDs surface endows them with excellent water re-dispersibility that outperforms those of most commercial nanomaterials. Photothermal therapeutic property of the ACDs is mechanistically described by non-radiative transitions of excited electrons at 808 nm via internal conversions and vibrational relaxations. Consequently, the ACDs offer cancer photothermal therapy in mice within 15 days post-exposure to one-time near infrared irradiation. This pioneering study showcases the first utilization of asphaltenes-based materials for cancer therapy and is expected to arouse further utilization of such materials in various cancer theranostics.

Recent progress of functional nano-chitosan in pharmaceutical and biomedical applications: An updated review

Chitosan is a deacylated derivative of chitin, which is a naturally occurring polysaccharide found in the shells of crustaceans. Chitosan's biocompatibility, physicochemical and mechanical properties qualify it as an excellent candidate for biomedical and pharmaceutical applications. Furthermore, the nanoengineering of chitosan enhances its functional and desirable properties for various applications. Additional functionalization of nano-chitosan is possible using various crosslinkers via chemical modification of hydroxyl or amino groups chitosan. This advanced functionalized nano-chitosan enables drug stability, site-specific delivery, controlled release, and sustainable pharmacodynamic properties. It is also used as a regenerative medicine for wound healing, bone and dental repair, biosensing and disease detection, tissue engineering, etc. Therefore, this review discusses the functionalization of nano-chitosan. A brief discussion is provided on the applications of nano-chitosan in the pharmaceutical industry such as drug carriers, targeted delivery, and controlled release, as well as in the biomedical industry, including wound healing, bone, and dental repair. Additionally, the disease detection using nano-chitosan has been investigated. Lastly, future perspectives and concluding remarks are presented.

Synthesis of bis(2-aminoethyl)amine functionalized mesoporous silica (SBA-15) adsorbent for selective adsorption of Pb2+ ions from wastewater

Rapid growth in the industry has released large quantities of contaminants, particularly metal discharges into the environment. Heavy metal poisoning in water bodies has become a major problem due to its toxicity to living organisms. In this study, we developed a 3-chloropropyl triethoxysilane incorporated mesoporous silica nanoparticle (SBA-15) based adsorbent utilizing the sol-gel process and Pluronic 123 (P123) as a structure-directing surfactant. Furthermore, the produced SBA-15 NPs were functionalized with bis(2-aminoethyl)amine (BDA) using the surface grafting approach. The physical and chemical properties of the prepared SBA-15@BDA NPs were determined using a variety of instruments, including small-angle X-ray diffraction (SAXS), Fourier-transform infrared (FTIR), scanning electron microscope (SEM), N2 adsorption-desorption, thermogravimetric, particle size distribution, and zeta potential analysis. The MSN has a large surface area of up to 574 m2/g, a pore volume of 0.57 cm3/g, and a well-ordered mesoporous nanostructure with an average pore size of 3.6 nm. The produced SBA-15@BDA NPs were used to adsorb selectively to lead (Pd2+) ions from an aqueous solution. The adsorption study was performed under various conditions, including the influence of solution pH, adsorbent dose, adsorption kinetics, adsorption selectivity in the presence of competing metal ions, and reusability. The results of the kinetic study demonstrated that SBA-15@BDA NPs absorb selectively Pb2+ ions via chemisorption. The SBA-15@BDA NPs show Pb2+ ions with a maximum adsorption capacity of ~ 88% and an adsorbed quantity of approximately ~ 112 mg/g from the studied aqueous solution. The adsorption mechanism relies on coordination bonding between Pb2+ ions and surface-functionalized amine groups on SBA-15@BDA NPs. Furthermore, the proposed SBA-15@BDA NPs adsorbent demonstrated excellent reusability over five cycles without significantly reducing adsorption performance. As a consequence, SBA-15@BDA NPs might serve as an effective adsorbent for the selective removal of Pb2+ ions from aqueous effluent.

Chitosan- and hyaluronic acid-based nanoarchitectures in phototherapy: Combination cancer chemotherapy, immunotherapy and gene therapy

Cancer phototherapy has been introduced as a new potential modality for tumor suppression. However, the efficacy of phototherapy has been limited due to a lack of targeted delivery of photosensitizers. Therefore, the application of biocompatible and multifunctional nanoparticles in phototherapy is appreciated. Chitosan (CS) as a cationic polymer and hyaluronic acid (HA) as a CD44-targeting agent are two widely utilized polymers in nanoparticle synthesis and functionalization. The current review focuses on the application of HA and CS nanostructures in cancer phototherapy. These nanocarriers can be used in phototherapy to induce hyperthermia and singlet oxygen generation for tumor ablation. CS and HA can be used for the synthesis of nanostructures, or they can functionalize other kinds of nanostructures used for phototherapy, such as gold nanorods. The HA and CS nanostructures can combine chemotherapy or immunotherapy with phototherapy to augment tumor suppression. Moreover, the CS nanostructures can be functionalized with HA for specific cancer phototherapy. The CS and HA nanostructures promote the cellular uptake of genes and photosensitizers to facilitate gene therapy and phototherapy. Such nanostructures specifically stimulate phototherapy at the tumor site, with particle toxic impacts on normal cells. Moreover, CS and HA nanostructures demonstrate high biocompatibility for further clinical applications.

Natural Polymeric Nanobiocomposites for Anti-Cancer Drug Delivery Therapeutics: A Recent Update

Cancer is one of the most common lethal diseases and the leading cause of mortality worldwide. Effective cancer treatment is a global problem, and subsequent advancements in nanomedicine are useful as substitute management for anti-cancer agents. Nanotechnology, which is gaining popularity, enables fast-expanding delivery methods in science for curing diseases in a site-specific approach, utilizing natural bioactive substances because several studies have established that natural plant-based bioactive compounds can improve the effectiveness of chemotherapy. Bioactive, in combination with nanotechnology, is an exceptionally alluring and recent development in the fight against cancer. Along with their nutritional advantages, natural bioactive chemicals may be used as chemotherapeutic medications to manage cancer. Alginate, starch, xanthan gum, pectin, guar gum, hyaluronic acid, gelatin, albumin, collagen, cellulose, chitosan, and other biopolymers have been employed successfully in the delivery of medicinal products to particular sites. Due to their biodegradability, natural polymeric nanobiocomposites have garnered much interest in developing novel anti-cancer drug delivery methods. There are several techniques to create biopolymer-based nanoparticle systems. However, these systems must be created in an affordable and environmentally sustainable way to be more readily available, selective, and less hazardous to increase treatment effectiveness. Thus, an extensive comprehension of the various facets and recent developments in natural polymeric nanobiocomposites utilized to deliver anti-cancer drugs is imperative. The present article provides an overview of the latest research and developments in natural polymeric nanobiocomposites, particularly emphasizing their applications in the controlled and targeted delivery of anti-cancer drugs.

Recent advances in nanoparticle-based photothermal therapy for breast cancer

Breast cancer is one of the most common cancers among women that is associated with high mortality. Conventional treatments including surgery, radiotherapy, and chemotherapy, which are not effective enough and have disadvantages such as toxicity and damage to healthy cells. Photothermal therapy (PTT) of cancer cells has been took great attention by researchers in recent years due to the use of light radiation and heat generation at the tumor site, which thermal ablation is considered a minimally invasive method for the treatment of breast cancer. Nanotechnology has opened up a new perspective in the treatment of breast cancer using PTT method. Through NIR light absorption, researchers applied various nanostructures because of their specific nature of penetrating and targeting tumor tissue, increasing the effectiveness of PTT, and combining it with other treatments. If PTT is used with common cancer treatments, it can dramatically increase the effectiveness of treatment and reduce the side effects of other methods. PTT performance can also be improved by hybridizing at least two different nanomaterials. Nanoparticles that intensely absorb light and increase the efficiency of converting light into heat can specifically kill tumors through hyperthermia of cancer cells. One of the main reasons that have increased the efficiency of nanoparticles in PTT is their permeability and durability effect and they can accumulate in tumor tissue. Targeted PTT can be provided by incorporating specific ligands to target receptors expressed on the surface of cancer cells on nanoparticles. These nanoparticles can specifically target cancer cells by maintaining the surface area and increasing penetration. In this study, we briefly introduce the performance of light therapy, application of metal nanoparticles, polymer nanoparticles, carbon nanoparticles, and hybrid nanoparticles for use in PTT of breast cancer.

Polysaccharide-based electroconductive hydrogels: Structure, properties and biomedical applications

Architecting an appropriate platform for biomedical applications requires setting a balance between simplicity and complexity. Polysaccharides (PSAs) play essential roles in our life in food resources, structural materials, and energy storage capacitors. Moreover, the diversity and abundance of PSAs have made them an indispensable part of food ingredients and cosmetics. PSA-based hydrogels have been extensively reviewed in biomedical applications. These hydrogels can be designed in different forms to show optimum performance. For instance, electroactive PSA-based hydrogels respond under an electric stimulus. Such performance can be served in stimulus drug release and determining cell fate. This review classifies and discusses the structure, properties, and applications of the most important polysaccharide-based electroactive hydrogels (agarose, alginate, chitosan, cellulose, and dextran) in medicine, focusing on their usage in tissue engineering, flexible electronics, and drug delivery applications.

Chitosan: A versatile bio-platform for breast cancer theranostics

Breast cancer is considered one of the utmost neoplastic diseases globally, with a high death rate of patients. Over the last decades, many approaches have been studied to early diagnose and treat it, such as chemotherapy, hormone therapy, immunotherapy, and MRI and biomarker tests; do not show the optimal efficacy. These existing approaches are accompanied by severe side effects, thus recognizing these challenges, a great effort has been done to find out the new remedies for breast cancer. Main finding: Nanotechnology opened a new horizon to the treatment of breast cancer. Many nanoparticulate platforms for the diagnosis of involved biomarkers and delivering antineoplastic drugs are under either clinical trials or just approved by the Food and Drug Administration (FDA). It is well known that natural phytochemicals are successfully useful to treat breast cancer because these natural compounds are safer, available, cheaper, and have less toxic effects. Chitosan is a biocompatible and biodegradable polymer. Further, it has outstanding features, like chemical functional groups that can easily modify our interest with an exceptional choice of promising applications. Abundant studies were directed to assess the chitosan derivative-based nanoformulation's abilities in delivering varieties of drugs. However, the role of chitosan in diagnostics and theranostics not be obligated. The present servey will discuss the application of chitosan as an anticancer drug carrier such as tamoxifen, doxorubicin, paclitaxel, docetaxel, etc. and also, its role as a theranostics (i.e. photo-responsive and thermo-responsive) moieties. The therapeutic and theranostic potential of chitosan in cancer is promising and it seems that to have a good potential to get to the clinic.

Photoacoustic Properties of Polypyrrole Nanoparticles

Photoacoustic imaging, an emerging modality, provides supplemental information to ultrasound imaging. We investigated the properties of polypyrrole nanoparticles, which considerably enhance contrast in photoacoustic images, in relation to the synthesis procedure and to their size. We prepared polypyrrole nanoparticles by water-based redox precipitation polymerization in the presence of ammonium persulphate (ratio nPy:nOxi 1:0.5, 1:1, 1:2, 1:3, 1:5) or iron(III) chloride (nPy:nOxi 1:2.3) acting as an oxidant. To stabilize growing nanoparticles, non-ionic polyvinylpyrrolidone was used. The nanoparticles were characterized and tested as a photoacoustic contrast agent in vitro on an imaging platform combining ultrasound and photoacoustic imaging. High photoacoustic signals were obtained with lower ratios of the oxidant (nPy:nAPS ≥ 1:2), which corresponded to higher number of conjugated bonds in the polymer. The increasing portion of oxidized structures probably shifted the absorption spectra towards shorter wavelengths. A strong photoacoustic signal dependence on the nanoparticle size was revealed; the signal linearly increased with particle surface. Coated nanoparticles were also tested in vivo on a mouse model. To conclude, polypyrrole nanoparticles represent a promising contrast agent for photoacoustic imaging. Variations in the preparation result in varying photoacoustic properties related to their structure and allow to optimize the nanoparticles for in vivo imaging.

Fluorescence/photoacoustic imaging-guided nanomaterials for highly efficient cancer theragnostic agent

Imaging modalities combined with a multimodal nanocomposite contrast agent hold great potential for significant contributions in the biomedical field. Among modern imaging techniques, photoacoustic (PA) and fluorescence (FL) imaging gained much attention due to their non-invasive feature and the mutually supportive characteristic in terms of spatial resolution, penetration depth, imaging sensitivity, and speed. In this present study, we synthesized IR783 conjugated chitosan-polypyrrole nanocomposites (IR-CS-PPy NCs) as a theragnostic agent used for FL/PA dual-modal imaging. A customized FL and photoacoustic imaging system was constructed to perform required imaging experiments and create high-contrast images. The proposed nanocomposites were confirmed to have great biosafety, essentially a near-infrared (NIR) absorbance property with enhanced photostability. The in vitro photothermal results indicate the high-efficiency MDA-MB-231 breast cancer cell ablation ability of IR-CS-PPy NCs under 808 nm NIR laser irradiation. The in vivo PTT study revealed the complete destruction of the tumor tissues with IR-CS-PPy NCs without further recurrence. The in vitro and in vivo results suggest that the demonstrated nanocomposites, together with the proposed imaging systems could be an effective theragnostic agent for imaging-guided cancer treatment.

Advances in Cancer Therapeutics: Conventional Thermal Therapy to Nanotechnology-Based Photothermal Therapy

In this review, advancement in cancer therapy that shows a transition from conventional thermal therapies to laser-based photothermal therapies is discussed. Laser-based photothermal therapies are gaining popularity in cancer therapeutics due to their overall outcomes. In photothermal therapy, light is converted into heat to destruct the various types of cancerous growth. The role of nanoparticles as a photothermal agent is emphasized in this review article. Magnetic, as well as non-magnetic, nanoparticles have been effectively used in the photothermal-based cancer therapies. The discussion includes a critical appraisal of in vitro and in vivo, as well as the latest clinical studies completed in this area. Plausible evidence suggests that photothermal therapy is a promising avenue in the treatment of cancer.

A Multispectral Photoacoustic Tracking Strategy for Wide-Field and Real-Time Monitoring of Macrophages in Inflammation

Inflammation is a common defensive response of the vascular system that involves the activation and mediation of immune cell and stem cell homing. However, it is usually hard to track and analyze the real-time status of these cell types toward the inflammation microenvironment in a large field of view with desired resolution. Here, we designed and synthesized near-infrared absorbing semiconducting polymer nanoparticles, BBT-TQP-NP (BTNPs), as the cell tracker and utilized their photoacoustic activity to unveil the targeting behaviors of macrophages, neutrophils, and mesenchymal stem cells to the inflamed sites in mice. Facilitated by multispectral optical-resolution photoacoustic microscopy (ORPAM), we can continuously monitor the in vivo photoacoustic signals of the labeled cells with cellular resolution in a wide-field (a circle field-of-view with a diameter of 9 mm). In addition, the highly sensitive observation of vascular microstructures and labeled cells can reveal the time-dependent accumulating behaviors of various cell types toward inflammation sites. As a result, our study offers an effective and promising tracking strategy to analyze the in vivo status and fate of functional cells in targeting the diseased/damaged regions.

Photoacoustic Neuroimaging - Perspectives on a Maturing Imaging Technique and its Applications in Neuroscience

A prominent goal of neuroscience is to improve our understanding of how brain structure and activity interact to produce perception, emotion, behavior, and cognition. The brain's network activity is inherently organized in distinct spatiotemporal patterns that span scales from nanometer-sized synapses to meter-long nerve fibers and millisecond intervals between electrical signals to decades of memory storage. There is currently no single imaging method that alone can provide all the relevant information, but intelligent combinations of complementary techniques can be effective. Here, we thus present the latest advances in biomedical and biological engineering on photoacoustic neuroimaging in the context of complementary imaging techniques. A particular focus is placed on recent advances in whole-brain photoacoustic imaging in rodent models and its influential role in bridging the gap between fluorescence microscopy and more non-invasive techniques such as magnetic resonance imaging (MRI). We consider current strategies to address persistent challenges, particularly in developing molecular contrast agents, and conclude with an overview of potential future directions for photoacoustic neuroimaging to provide deeper insights into healthy and pathological brain processes.

Antibiofilm and antimicrobial efficacy evaluation of polypyrrole nanotubes embedded in aminated gum acacia based nanocomposite

The sustainable development of natural polysaccharide-based hybrid composites is highly important for the effective replacement of metal nanoparticles in diverse applications. Here, polypyrrole nanotubes (PPyNTs) were embedded on the surface of aminated gum acacia (AGA) to produce ecofriendly nanocomposites for biomedical applications. The morphology of a PPyNT-enhanced AGA (PPyNT@AGA) hybrid nanocomposite was studied by scanning electron microscopy and transmission electron microscopy and their affirmed interactions were characterised by X-ray diffraction, Raman, Fourier transform-infrared and UV-visible spectroscopy. Interestingly, the prepared PPyNT@AGA nanocomposite exhibited 90% biofilm inhibition against gram-negative Pseudomonas aeruginosa, gram-positive Streptococcus pneumoniae and fungal strain Candida albicans with promising antimicrobial performance. This study establishes the good inhibition of a PPyNT@AGA hybrid composite against various microorganisms. The stability of the nanocomposite coupled with antimicrobial activity enables an effective strategy for diagnosing and controlling pathogens.

Biomaterials in treatment of Alzheimer's disease

Alzheimer's disease (AD) is a non-recoverable progressive neurodegenerative disorder most prevalent but not limited to the old age population. After all the scientific efforts, there are still many unmet criteria and loopholes in available treatment and diagnostic strategies, limiting their efficacy. The poor drug efficacy is attributed to various biological hurdles, including blood-brain barrier (BBB) and peripheral side effects as most prominent ones and the lack of promising carriers to precisely deliver the drug to the brain by conserving its therapeutic potency. The increasing disease prevalence and unavailability of effective therapy calls for developing a more innovative, convenient and affordable way to treat AD. To fulfill such need, researchers explored various biomaterials to develop potential vectors or other forms to target the bioactives in the brain by preserving their inherent properties, improving the existing lacuna like poor solubility, permeability and bioavailability etc. and minimize the side effect. The unique characteristic properties of biomaterials are used to develop different drug carriers, surface modifying target active ligands, functional carriers, drug conjugate, biosensing probe, diagnostic tool and many more. The nanoparticulate system and other colloidal carriers like hydrogel and biodegradable scaffold can effectively target the drug moieties to the brain. Also, the use of different target-acting ligands and stimuli-responsive carriers assures the site-specificity and controlled release at the desired site by interaction with receptors and various exo- and endogenous stimuli. This review article has highlighted the application of biomaterials for targeting the drug to the brain and as promising diagnostic tools to detect the markers for better AD management. The work particularly focuses on the use of biomaterials as smart drug carriers including pH, thermo, photo, electro and magnetically triggered system; novel drug carriers for brain targeting including polymeric carriers (polymeric nanoparticle, dendrimer and polymeric micelle); lipid carrier (liposome, nanoemulsion, NLC and SLN); inorganic nanoparticles (quantum dots, gold nanoparticles etc.); and other drug vectors (hydrogel, biodegradable scaffold, and carbon nanotube) in treatment of AD. It also highlighted the application of some novel carrier systems and biomaterials as biosensor and other diagnostic tools for early and precise AD diagnosis.

Metal-Free Organo-Theranostic Nanosystem with High Nitroxide Stability and Loading for Image-Guided Targeted Tumor Therapy

The desire for all-organic-composed nanoparticles (NPs) of considerable biocompatibility to simultaneously diagnose and treat cancer is undeniably interminable. Heretofore, metal-based agents dominate the landscape of available magnetic resonance imaging (MRI) contrast agents and photothermal therapeutic agents, but with associated metal-specific downsides. Here, an all-organic metal-free nanoprobe, whose appreciable biocompatibility is synergistically contributed by its tetra-organo-components, is developed as a viable alternative to metal-based probes for MRI-guided tumor-targeted photothermal therapy (PTT). This rationally entails a glycol chitosan (GC)-linked polypyrrole (PP) nanoscaffold that provides abundant primary and secondary amino groups for amidation with the carboxyl groups in a nitroxide radical (TEMPO) and folic acid (FA), to obtain GC-PP@TEMPO-FA NPs. Advantageously, the appreciably benign GC-PP@TEMPO-FA features high nitroxide loading (r₁ = 1.58 mM^-1 s^-1) and in vivo nitroxide-reduction resistance, prolonged nitroxide-systemic circulation times, appreciable water dispersibility, potential photodynamic therapeutic and electron paramagnetic resonance imaging capabilities, considerable biocompatibility, and ultimately achieves a 17 h commensurate MRI contrast enhancement. Moreover, its GC component conveys a plethora of PP to tumor sites, where FA-mediated tumor targeting enables substantial NP accumulation with consequential near-complete tumor regression within 16 days in an MRI-guided PTT. The present work therefore promotes the engineering of organic-based metal-free biocompatible NPs in synergism, in furtherance of tumor-targeted image-guided therapy.

A portable device with low-power consumption for monitoring mouse vital signs during in vivo photoacoustic imaging and photothermal therapy

OBJECTIVE

The aim of this study was to monitor the physiological changes and cytotoxic effects of exogenous contrast agents during photoacoustic imaging (PAI) and photothermal therapy (PTT). In this paper, a low-power telemetric device for mouse vital signs monitoring was designed and demonstrated.

APPROACH

The power consumption was optimized through hardware and software co-design with a 17% increased operating time compared with typical operation. To demonstrate the feasibility of the monitoring device, PAI and PTT experiments with chitosan-polypyrrole nanocomposites (CS-PPy NCs) as exogenous contrast agents were conducted. Herein, the physiological variation in groups of mice with different CS-PPy NC concentrations was observed and analyzed.

MAIN RESULTS

The experimental results indicated the influence of CS-PPy NCs and anesthesia on mouse vital signs in PAI and PTT. Additionally, the association between core temperature, heart rate, and saturation of peripheral oxygen (SpO₂) during PAI and PTT was shown. The strong near-infrared absorbance of exogenous contrast agents could account for the increase in mouse core temperature and tumor temperature in this study. Furthermore, high cross-correlation values between core temperature, heart rate, and SpO₂ were demonstrated to explain the fluctuation of mouse vital signs during PAI and PTT.

SIGNIFICANCE

A design of a vital signs monitoring device, with low power consumption, was introduced in this study. A high cross correlation coefficient of mouse vital signs and the effects of CS-PPy NCs were observed, which explained the mouse physiological variation during the PAI and PTT experiments.

A Hybrid Organo-Nanotheranostic Platform of Superlative Biocompatibility for Near-Infrared-Triggered Fluorescence Imaging and Synergistically Enhanced Ablation of Tumors

The quest for an all-organic nanosystem with negligible cytotoxicity and remarkable in vivo tumor theranostic capability is inescapably unending. Hitherto, the landscape of available photothermal agents is dominated by metal-based nanoparticles (NPs) with attendant in vivo negatives. Here, an all-organic-composed theranostic nanosystem with outstanding biocompatibility for fluorescence image-guided tumor photothermal therapy, and as a potential alternative to metal-based photothermal agents is developed. This is rationally achieved by compartmentalizing indocyanine green (ICG) in glycol chitosan (GC)-polypyrrole (PP) nanocarrier to form hybrid ICG@GC-PP NPs (≈65 nm). The compartmentalization strategy, alongside the high photothermal conversion ability of PP jointly enhances the low photostability of free ICG. Advantageously, ICG@GC-PP is endowed with an impeccable in vivo performance by the well-known biocompatibility track records of its individual tri organo-components (GC, PP, and ICG). As a proof of concept, ICG@GC-PP NPs enables a sufficiently prolonged tumor diagnosis by fluorescence imaging up to 20 h post-injection. Furthermore, owing to the complementary heating performances of PP and ICG, ICG@GC-PP NPs-treated mice by one-time near-infrared irradiation exhibit total tumor regression within 14 days post-treatment. Therefore, leveraging the underlying benefits of this study will help to guide the development of new all-organic biocompatible systems in synergism, for safer tumor theranostics.

Photoacoustic image-guided interventions

Photoacoustic imaging has demonstrated its potential for diagnosis over the last few decades. In recent years, its unique imaging capabilities, such as detecting structural, functional and molecular information in deep regions with optical contrast and ultrasound resolution, have opened up many opportunities for photoacoustic imaging to be used during image-guided interventions. Numerous studies have investigated the capability of photoacoustic imaging to guide various interventions such as drug delivery, therapies, surgeries, and biopsies. These studies have demonstrated that photoacoustic imaging can guide these interventions effectively and non-invasively in real-time. In this minireview, we will elucidate the potential of photoacoustic imaging in guiding active and passive drug deliveries, photothermal therapy, and other surgeries and therapies using endogenous and exogenous contrast agents including organic, inorganic, and hybrid nanoparticles, as well as needle-based biopsy procedures. The advantages of photoacoustic imaging in guided interventions will be discussed. It will, therefore, show that photoacoustic imaging has great potential in real-time interventions due to its advantages over current imaging modalities like computed tomography, magnetic resonance imaging, and ultrasound imaging.

Enhanced Catalytic Activity of Gold@Polydopamine Nanoreactors with Multi-compartment Structure Under NIR Irradiation

Photothermal conversion (PTC) nanostructures have great potential for applications in many fields, and therefore, they have attracted tremendous attention. However, the construction of a PTC nanoreactor with multi-compartment structure to achieve the combination of unique chemical properties and structural feature is still challenging due to the synthetic difficulties. Herein, we designed and synthesized a catalytically active, PTC gold (Au)@polydopamine (PDA) nanoreactor driven by infrared irradiation using assembled PS-b-P2VP nanosphere as soft template. The particles exhibit multi-compartment structure which is revealed by 3D electron tomography characterization technique. They feature permeable shells with tunable shell thickness. Full kinetics for the reduction reaction of 4-nitrophenol has been investigated using these particles as nanoreactors and compared with other reported systems. Notably, a remarkable acceleration of the catalytic reaction upon near-infrared irradiation is demonstrated, which reveals for the first time the importance of the synergistic effect of photothermal conversion and complex inner structure to the kinetics of the catalytic reduction. The ease of synthesis and fresh insights into catalysis will promote a new platform for novel nanoreactor studies.

Photothermal inactivation of methicillin-resistant Staphylococcus aureus: anti-biofilm mediated by a polypyrrole-carbon nanocomposite

Widespread resistance to antibiotics amongst pathogens has become a tremendous challenge of high morbidity and mortality rates which increases the needs to exploring novel methods of treatment. An efficient antimicrobial procedure to root out pathogenic bacteria is photothermal therapy. In this study, antimicrobial effects of a polypyrrole-carbon nanocomposite (PPy-C) upon laser irradiation in order to destroy the pathogenic gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA) were assessed. The bacterial cells were incubated with 500, 750 and 1000 μg ml-1 concentrations of PPy-C and irradiated with an 808-nm laser at a power density of 1.0 W cm-2. To indicate the biocompatibility and toxic effect of the nanocomposite without and with laser irradiation, the authors counted the number of CFUs and compared it to an untreated sample. Antibacterial mechanisms of PPy-C were assessed through temperature increment, reactive oxygen species production, and protein and DNA leakages. Photothermal heating assay showed that 26°C temperature increases in the presence of 1000 µg ml-1 PPy-C led to >98% killing of MRSA. Furthermore, 20 min radiation of near-infrared light to PPy-C in different concentrations indicated destruction and reduction in the MRSA biofilm formation. Therefore, PPy-C was introduced as a photothermal absorber with a bactericidal effect in MRSA.

Enabling biodegradable functional biomaterials for the management of neurological disorders

An increasing number of patients are being diagnosed with neurological diseases, but are rarely cured because of the lack of curative therapeutic approaches. This situation creates an urgent clinical need to develop effective diagnosis and treatment strategies for repair and regeneration of injured or diseased neural tissues. In this regard, biodegradable functional biomaterials provide promising solutions to meet this demand owing to their unique responsiveness to external stimulation fields, which enable neuro-imaging, neuro-sensing, specific targeting, hyperthermia treatment, controlled drug delivery, and nerve regeneration. This review discusses recent progress in the research and development of biodegradable functional biomaterials including electroactive biomaterials, magnetic materials and photoactive biomaterials for the management of neurological disorders with emphasis on their applications in bioimaging (photoacoustic imaging, MRI and fluorescence imaging), biosensing (electrochemical sensing, magnetic sensing and opical sensing), and therapy strategies (drug delivery, hyperthermia treatment, and tissue engineering). It is expected that this review will provide an insightful discussion on the roles of biodegradable functional biomaterials in the diagnosis and treatment of neurological diseases, and lead to innovations for the design and development of the next generation biodegradable functional biomaterials.

Gold Nanoparticles for Photothermal Cancer Therapy

Gold is a multifunctional material that has been utilized in medicinal applications for centuries because it has been recognized for its bacteriostatic, anticorrosive, and antioxidative properties. Modern medicine makes routine, conventional use of gold and has even developed more advanced applications by taking advantage of its ability to be manufactured at the nanoscale and functionalized because of the presence of thiol and amine groups, allowing for the conjugation of various functional groups such as targeted antibodies or drug products. It has been shown that colloidal gold exhibits localized plasmon surface resonance (LPSR), meaning that gold nanoparticles can absorb light at specific wavelengths, resulting in photoacoustic and photothermal properties, making them potentially useful for hyperthermic cancer treatments and medical imaging applications. Modifying gold nanoparticle shape and size can change their LPSR photochemical activities, thereby also altering their photothermal and photoacoustic properties, allowing for the utilization of different wavelengths of light, such as light in the near-infrared spectrum. By manufacturing gold in a nanoscale format, it is possible to passively distribute the material through the body, where it can localize in tumors (which are characterized by leaky blood vessels) and be safely excreted through the urinary system. In this paper, we give a quick review of the structure, applications, recent advancements, and potential future directions for the utilization of gold nanoparticles in cancer therapeutics.

Assessing hemorrhagic shock: Feasibility of using an ultracompact photoacoustic microscope

Hemorrhagic shock, as an important clinical issue, is regarding as a critical disease with a high mortality rate. Unfortunately, existing clinical technologies are inaccessible to assess the hemorrhagic shock via hemodynamics in microcirculation. Here, we propose an ultracompact photoacoustic microscope to assess hemorrhagic shock using a rat model and demonstrate its clinical feasibility by visualizing buccal microcirculation of healthy volunteers. Both functional and morphological features of the microvascular network including concentration of total hemoglobin (C_HbT ), number of blood vessels (VN), small vascular density (SVD) and vascular diameter (VD) were derived to assess the microvascular hemodynamics of different organs. Animal studies show the feasibility of the proposed tool to assess and stage the hemorrhagic shock via microcirculation. in vivo oral imaging of healthy volunteers indicates the translational possibility of this technique for clinical evaluation of hemorrhagic shock.

Albumin-functionalized CuFeS2/photosensitizer nanohybrid for single-laser-induced folate receptor-targeted photothermal and photodynamic therapy

Multimodal therapy is an emerging medical intervention to overcome the current limitation in cancer therapy combining treatment modalities with different mechanisms of action to eradicate tumors. This study demonstrates a targeted multifunctional bovine serum albumin (BSA)-functionalized CuFeS₂/chlorin e6 (Ce6) for synergistic photothermal therapy (PTT) and photodynamic therapy (PDT) effects. The CuFeS₂ nanocrystals were synthesized through a simple heating-up approach and transferred into an aqueous phase using BSA in an ultrasonic-assisted microemulsion method. The as-prepared CuFeS₂@BSA nanoparticles further conjugated with folic acid (FA) followed by attachment of Ce6 to form the Ce6:CuFeS₂@BSA-FA nanohybrid with improved solubility and strong near-infrared (NIR) absorbance and fluorescence. It is the first report to fabricate the targeted Ce6:CuFeS₂@BSA-FA hybrid and evaluates their synergistic PTT/PDT effect using a single laser. The Ce6:CuFeS₂@BSA-FA hybrid showed lower toxicity in vitro (HeLa and HepG2 cells) and in vivo (zebrafish embryos), while they are selectively recognized and internalized by HeLa cells that over-express folate receptors. Compared to each modality applied separately, the combined single-laser-induced PTT and PDT treatment showed the enhanced generation of heat and reactive oxygen species (ROS) with synergistic cancer killing under 671 nm laser irradiation (10 min, 1 W/cm²). As a biocompatible targeted nanoprobe, the multifunctional nanohybrid holds promise in combined PDT/PTT synergistic therapy to achieve better efficacy.

Biofunctional core-shell polypyrrole-polyethylenimine nanocomplex for a locally sustained photothermal with reactive oxygen species enhanced therapeutic effect against lung cancer

BACKGROUND

Polymeric delivery systems have been elucidated over the last few years as an approach of achieving high therapeutic effect to the local site of malignant disease patients who have cancer. Polypyrrole (Ppy) is a potential organic conducting polymer which has long been recognized as a versatile material due to its excellent stability, conductive properties, and great absorbance in the range of near-infrared (NIR). It is tremendously versatile for use in various biomedical fields such as cancer therapy. NIR irradiation-activated treatment platform technologies are now being considered to be novel and exciting options in potential nanomedicine. However, the realistic photothermal use of Ppy-applied nanomaterials is yet in its early phase, and there are a few disadvantages of Ppy, such as its water insolubility. In the clinic, the common approach for treatment of lung cancer is the delivery of therapeutic active substances through intratumoral administration. Nevertheless, the tumor uptake, regional retention, mechanism of treatment, and tissue organ penetration regarding the developed strategy of this nanomaterial with photothermal hyperthermia are important issues for exerting effective cancer therapy.

MATERIALS AND METHODS

In this study, we developed a cationic Ppy-polyethylenimine nanocomplex (NC) with photothermal hyperthermia to study its physicochemical characteristics, including size distribution, zeta potential, and transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared morphology. We also examined the cellular uptake effect on lung cancer cells, the photothermal properties, intracellularly generated reactive oxygen species (ROS), and cytotoxicity.

RESULTS

The results suggested that this nanocarrier system was able to effectively attach onto lung cancer cells for subsequent endocytosis. The NCs taken up were able to absorb NIR and then converted the NIR light into local hyperthermia with its intracellular photothermal performance to provide local hyperthermic treatment. This regionally generated hyperthermia also induced ROS formation and improved the killing of lung cancer cells as a promising local photothermal therapy.

CONCLUSION

This development of a nanocarrier would bring a novel therapeutic strategy for lung cancer in the future.

Magnetic Regulation of Thermo-Chemotherapy from a Cucurbit[7]uril-Crosslinked Hybrid Hydrogel

The fabrication, characterization, and therapy efficiency of a noncovalent-bonded hydrogel network, which is assembled by utilizing cucurbit[7]uril as a supramolecular linker to "stick" superparamagnetic γ-Fe₂ O₃ nanoparticles onto the polymer backbone of catechol-functionalized chitosan are described. The unique barrel-shaped structure of cucurbit[7]uril not only facilitates host-guest recognition with the catechol derivatives, but also forms robust electrostatic interactions between its carbonyl portals and the γ-Fe₂ O₃ nanoparticles in a supramolecular manner, which leaves the physical and chemical properties of the nanoparticles intact. The γ-Fe₂ O₃ nanoparticles display vibrational movement and heat generation under an alternating magnetic field, endowing the formed hybrid supramolecular hydrogel with both thermo- and chemotherapy modalities, which are demonstrated both in vitro and in vivo. Here, a facile strategy is introduced to construct noncovalent interactions between a polymer matrix and the incorporated nanoparticles, which is amendable to a wide range of biomedical and industrial applications.

Contemporary Polymer-Based Nanoparticle Systems for Photothermal Therapy

Current approaches for the treatment of cancer, such as chemotherapy, radiotherapy, immunotherapy, and surgery, are limited by various factors, such as inadvertent necrosis of healthy cells, immunological destruction, or secondary cancer development. Hyperthermic therapy is a promising strategy intended to mitigate many of the shortcomings associated with traditional therapeutic approaches. However, to utilize this approach effectively, it must be targeted to specific tumor sites to prevent adverse side effects. In this regard, photothermal therapy, using intravenously-administered nanoparticle materials capable of eliciting hyperthermic effects in combination with the precise application of light in the near-infrared spectrum, has shown promise. Many different materials have been proposed, including various inorganic materials such as Au, Ag, and Germanium, and C-based materials. Unfortunately, these materials are limited by concerns about accumulation and potential cytotoxicity. Polymer-based nanoparticle systems have been investigated to overcome limitations associated with traditional inorganic nanoparticle systems. Some of the materials that have been investigated for this purpose include polypyrrole, poly-(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS), polydopamine, and polyaniline. The purpose of this review is to summarize these contemporary polymer-based nanoparticle technologies to acquire an understanding of their current applications and explore the potential for future improvements.

Photoacoustic Imaging-Guided Photothermal Therapy with Tumor-Targeting HA-FeOOH@PPy Nanorods

Cancer theragnosis agents with both cancer diagnosis and therapy abilities would be the next generation of cancer treatment. Recently, nanomaterials with strong absorption in near-infrared (NIR) region have been explored as promising cancer theragnosis agents for bio-imaging and photothermal therapy (PTT). Herein, we reported the synthesis and application of a novel multifunctional theranostic nanoagent based on hyaluronan (HA)-coated FeOOH@polypyrrole (FeOOH@PPy) nanorods (HA-FeOOH@PPy NRs) for photoacoustic imaging (PAI)-guided PTT. The nanoparticles were intentionally designed with rod-like shape and conjugated with tumor-targeting ligands to enhance the accumulation and achieve the entire tumor distribution of nanoparticles. The prepared HA-FeOOH@PPy NRs showed excellent biocompatible and physiological stabilities in different media. Importantly, HA-FeOOH@PPy NRs exhibited strong NIR absorbance, remarkable photothermal conversion capability, and conversion stability. Furthermore, HA-FeOOH@PPy NRs could act as strong contrast agents to enhance PAI, conducting accurate locating of cancerous tissue, as well as precise guidance for PTT. The in vitro and in vivo photothermal anticancer activity results of the designed nanoparticles evidenced their promising potential in cancer treatment. The tumor-bearing mice completely recovered after 17 days of PTT treatment without obvious side effects. Thus, our work highlights the great potential of using HA-FeOOH@PPy NRs as a theranostic nanoplatform for cancer imaging-guided therapy.

Bioconversion of Chitin to Bioactive Chitooligosaccharides: Amelioration and Coastal Pollution Reduction by Microbial Resources

Chitin-metabolizing products are of high industrial relevance in current scenario due to their wide biological applications, relatively lower cost, greater abundance, and sustainable supply. Chitooligosaccharides have remarkably wide spectrum of applications in therapeutics such as antitumor agents, immunomodulators, drug delivery, gene therapy, wound dressings, as chitinase inhibitors to prevent malaria. Hypocholesterolemic and antimicrobial activities of chitooligosaccharides make them a molecule of choice for food industry, and their functional profile depends on the physicochemical characteristics. Recently, chitin-based nanomaterials are also gaining tremendous importance in biomedical and agricultural applications. Crystallinity and insolubility of chitin imposes a major hurdle in the way of polymer utilization. Chemical production processes are known to produce chitooligosaccharides with variable degree of polymerization and properties along with ecological concerns. Biological production routes mainly involve chitinases, chitosanases, and chitin-binding proteins. Development of bio-catalytic production routes for chitin will not only enhance the production of commercially viable chitooligosaccharides with defined molecular properties but will also provide a means to combat marine pollution with value addition.

A built-in electric field with nanoscale distinction for cell behavior regulation

To mimic the electrical properties of collagen fibrils on a bone surface, a built-in nanoscale electric field is formed on the surface of a polypyrrole (PPy) coating-decorated potassium-sodium niobate (KNN) piezoceramic. With the fabrication strategy, the piezoelectricity of KNN after polarization results in the formation of an electric field on the surface, which could be regulated by adjusting the polarization process. Then, conductive PPy nanoarrays (CPNAs) are obtained on the surfaces of the KNN piezoceramics. The conductive PPy transports the electric field to the coating surface, and the nanoarray morphology results in variations in the surface potential, leading to a built-in nanoscale electric field. Biological characterization indicates that CPNAs exhibit acceptable biocompatibility. Moreover, the nanoscale electric field regulates cell behavior, and the relatively high surface potential promotes cell proliferation, cell attachment and osteogenic differentiation.

Recent advances in near-infrared light-responsive nanocarriers for cancer therapy

In recent years, research has focused on the development of smart nanocarriers that can respond to specific stimuli. Among the various stimuli-responsive platforms for cancer therapy, near-infrared (NIR) light (700-1000nm)-responsive nanocarriers have gained considerable interest because of their deeper tissue penetration capacity, precisely controlled drug release, and minimal damage towards normal tissues. In this review, we outline various therapeutic applications of NIR-responsive nanocarriers in drug delivery, photothermal therapy (PTT), photodynamic therapy (PDT), and bioimaging. We also highlight recent trends towards NIR-responsive combinatorial therapy and multistimuli-responsive nanocarriers for improving therapeutic outcomes.

In vivo photoacoustic monitoring using 700-nm region Raman source for targeting Prussian blue nanoparticles in mouse tumor model

Photoacoustic imaging (PAI) is a noninvasive imaging tool to visualize optical absorbing contrast agents. Due to high ultrasonic resolution and superior optical sensitivity, PAI can be used to monitor nanoparticle-mediated cancer therapy. The current study synthesized Food and Drug Administration-approved Prussian blue (PB) in the form of nanoparticles (NPs) with the peak absorption at 712 nm for photoacoustically imaging tumor-bearing mouse models. To monitor PB NPs from the background tissue in vivo, we also developed a new 700-nm-region stimulated Raman scattering (SRS) source (pulse energy up to 200 nJ and repetition rate up to 50 kHz) and implemented optical-resolution photoacoustic microscopy (OR-PAM). The SRS-assisted OR-PAM system was able to monitor PB NPs in the tumor model with micrometer resolution. Due to strong light absorption at 712 nm, the developed SRS light yielded a two-fold higher contrast from PB NPs, in comparison with a 532-nm pumping source. The proposed laser source involved cost-effective and simple system implementation along with high compatibility with the fiber-based OR-PAM system. The study highlights the OR-PAM system in conjunction with the tunable-color SRS light source as a feasible tool to assist NP-mediated cancer therapy.

Prussian blue decorated mesoporous silica hybrid nanocarriers for photoacoustic imaging-guided synergistic chemo-photothermal combination therapy

Herein, Prussian blue decorated mesoporous silica PB@MSH-EDA NPs are fabricated for efficient photoacoustic imaging guided chemo-photothermal combination therapy.

Fe3O4@MnO2@PPy nanocomposites overcome hypoxia: magnetic-targeting-assisted controlled chemotherapy and enhanced photodynamic/photothermal therapy

Here, a multifunctional nanocomposite composed by a core of iron oxide (Fe₃O₄) and two shells of manganese dioxide (MnO₂) and polypyrrole (PPy) was successfully designed and synthesized for drug delivery and magnetic targeting assisted synergistic effects of chemotherapy and improved PDT/PTT.

Broadband absorption and enhanced photothermal conversion property of octopod-like Ag@Ag2S core@shell structures with gradually varying shell thickness

Photothermal conversion materials have promising applications in many fields and therefore they have attracted tremendous attention. However, the multi-functionalization of a single nanostructure to meet the requirements of multiple photothermal applications is still a challenge. The difficulty is that most nanostructures have specific absoprtion band and are not flexible to different demands. In the current work, we reported the synthesis and multi-band photothermal conversion of Ag@Ag2S core@shell structures with gradually varying shell thickness. We synthesized the core@shell structures through the sulfidation of Ag nanocubes by taking the advantage of their spatially different reactivity. The resulting core@shell structures show an octopod-like mopgorlogy with a Ag2S bulge sitting at each corner of the Ag nanocubes. The thickness of the Ag2S shell gradually increases from the central surface towards the corners of the structure. The synthesized core@shell structures show a broad band absorption spectrum from 300 to 1100 nm. Enhanced photothermal conversion effect is observed under the illuminations of 635, 808, and 1064 nm lasers. The results indicate that the octopod-like Ag@Ag2S core@shell structures have characteristics of multi-band photothermal conversion. The current work might provide a guidance for the design and synthesis of multifunctional photothermal conversion materials.

Marine natural pigments as potential sources for therapeutic applications

In recent years, marine natural pigments have emerged as a powerful alternative in the various fields of food, cosmetic, and pharmaceutical industries because of their excellent biocompatibility, bioavailability, safety, and stability. Marine organisms are recognized as a rich source of natural pigments such as chlorophylls, carotenoids, and phycobiliproteins. Numerous studies have shown that marine natural pigments have considerable medicinal potential and promising applications in human health. In this review, we summarize the marine natural pigments as potential sources for therapeutic applications, including: antioxidant, anticancer, antiangiogenic, anti-obesity, anti-inflammatory activities, drug delivery, photothermal therapy (PTT), photodynamic therapy (PDT), photoacoustic imaging (PAI), and wound healing. Marine natural pigments will offer a better platform for future theranostic applications.

Synthesis and In Vitro Performance of Polypyrrole-Coated Iron-Platinum Nanoparticles for Photothermal Therapy and Photoacoustic Imaging

Multifunctional nano-platform for the combination of photo-based therapy and photoacoustic imaging (PAI) for cancer treatment has recently attracted much attention to nanotechnology development. In this study, we developed iron-platinum nanoparticles (FePt NPs) with the polypyrrole (PPy) coating as novel agents for combined photothermal therapy (PTT) and PAI. The obtained PPy-coated FePt NPs (FePt@PPy NPs) showed excellent biocompatibility, photothermal stability, and high near-infrared (NIR) absorbance for the combination of PTT and PAI. In vitro investigation experimentally demonstrated the effectiveness of FePt@PPy NPs in killing cancer cells with NIR laser irradiation. Moreover, the phantom test of PAI used in conjunction with FePt@PPy NPs showed a strong photoacoustic signal. Thus, the novel FePt@PPy NPs could be considered as promising multifunctional nanoparticles for further applications of photo-based diagnosis and treatment.