Electrical-Charge-Mediated Cancer Cell Targeting via Protein Corona-Decorated Superparamagnetic Nanoparticles in a Simulated Physiological Environment

Application of 4D-Printed Magnetoresponsive FOGS Hydrogel Scaffolds in Auricular Cartilage Regeneration

3D-printed hydrogel scaffolds are widely utilized in auricular cartilage tissue engineering. However, issues such as graft-related inflammation, poor mechanical properties, and the lack of external modulation of 3D-printed scaffolds in vivo have raised significant concerns. To address these challenges, a "fried egg" structure is designed, consisting of chitosan-coated ferroferric oxide magnetic nanoparticles (Fe3O4@CS MNPs), which are uniformly incorporated into hydrogel. Through 4D printing technology, magnetoresponsive hydrogel scaffolds are constructed to overcome the aforementioned limitations. The results demonstrated that, compared to 3D printing, 4D-printed magnetic hydrogel scaffolds significantly enhanced cartilage tissue regeneration in both in vitro and in vivo environments when subjected to an external magnetic field (MF). Furthermore, the mechanical strength of regenerated cartilage approached to that of natural cartilage. The chitosan coating on the surface of MNPs exhibited anti-inflammatory and antibacterial properties, promoting M2 polarization of macrophages and suppressing graft-related inflammation and bacteria. Transcriptomic analysis confirmed that MNPs modulate macrophage immunity by activating JAK2/STAT3 signaling pathway. Taken together, a magnetoresponsive multifunctional scaffold is designed that can be externally controlled by magnetic fields to promote ear cartilage tissue regeneration. The regenerated cartilage exhibits excellent biocompatibility, anti-inflammatory, antibacterial properties, and mechanical performance, providing new insights for auricular cartilage tissue engineering.

Leveraging Artificial Intelligence and Machine Learning for Characterizing Protein Corona, Nanobiological Interactions, and Advancing Drug Discovery

Proteins are essential for all living organisms, playing key roles in biochemical reactions, structural support, signal transduction, and gene regulation. Their importance in biomedical research is highlighted by their role as drug targets in various diseases. The interactions between proteins and nanoparticles (NPs), including the protein corona's formation, significantly affect NP behavior, biodistribution, cellular uptake, and toxicity. Comprehending these interactions is pivotal for advancing the design of NPs to augment their efficacy and safety in biomedical applications. While traditional nanomedicine design relies heavily on experimental work, the use of data science and machine learning (ML) is on the rise to predict the synthesis and behavior of nanomaterials (NMs). Nanoinformatics combines computational simulations with laboratory studies, assessing risks and revealing complex nanobio interactions. Recent advancements in artificial intelligence (AI) and ML are enhancing the characterization of the protein corona and improving drug discovery. This review discusses the advantages and limitations of these approaches and stresses the importance of comprehensive datasets for better model accuracy. Future developments may include advanced deep-learning models and multimodal data integration to enhance protein function prediction. Overall, systematic research and advanced computational tools are vital for improving therapeutic outcomes and ensuring the safe use of NMs in medicine.

Surface Bio-engineered Polymeric Nanoparticles

Surface bio-engineering of polymeric nanoparticles (PNPs) has emerged as a cornerstone in contemporary biomedical research, presenting a transformative avenue that can revolutionize diagnostics, therapies, and drug delivery systems. The approach involves integrating bioactive elements on the surfaces of PNPs, aiming to provide them with functionalities to enable precise, targeted, and favorable interactions with biological components within cellular environments. However, the full potential of surface bio-engineered PNPs in biomedicine is hampered by obstacles, including precise control over surface modifications, stability in biological environments, and lasting targeted interactions with cells or tissues. Concerns like scalability, reproducibility, and long-term safety also impede translation to clinical practice. In this review, these challenges in the context of recent breakthroughs in developing surface-biofunctionalized PNPs for various applications, from biosensing and bioimaging to targeted delivery of therapeutics are discussed. Particular attention is given to bonding mechanisms that underlie the attachment of bioactive moieties to PNP surfaces. The stability and efficacy of surface-bioengineered PNPs are critically reviewed in disease detection, diagnostics, and treatment, both in vitro and in vivo settings. Insights into existing challenges and limitations impeding progress are provided, and a forward-looking discussion on the field's future is presented. The paper concludes with recommendations to accelerate the clinical translation of surface bio-engineered PNPs.

Aptamer-Based Smart Targeting and Spatial Trigger-Response Drug-Delivery Systems for Anticancer Therapy

In recent years, the field of drug delivery has witnessed remarkable progress, driven by the quest for more effective and precise therapeutic interventions. Among the myriad strategies employed, the integration of aptamers as targeting moieties and stimuli-responsive systems has emerged as a promising avenue, particularly in the context of anticancer therapy. This review explores cutting-edge advancements in targeted drug-delivery systems, focusing on the integration of aptamers and stimuli-responsive platforms for enhanced spatial anticancer therapy. In the aptamer-based drug-delivery systems, we delve into the versatile applications of aptamers, examining their conjugation with gold, silica, and carbon materials. The synergistic interplay between aptamers and these materials is discussed, emphasizing their potential in achieving precise and targeted drug delivery. Additionally, we explore stimuli-responsive drug-delivery systems with an emphasis on spatial anticancer therapy. Tumor microenvironment-responsive nanoparticles are elucidated, and their capacity to exploit the dynamic conditions within cancerous tissues for controlled drug release is detailed. External stimuli-responsive strategies, including ultrasound-mediated, photo-responsive, and magnetic-guided drug-delivery systems, are examined for their role in achieving synergistic anticancer effects. This review integrates diverse approaches in the quest for precision medicine, showcasing the potential of aptamers and stimuli-responsive systems to revolutionize drug-delivery strategies for enhanced anticancer therapy.

Fluorinated amphiphilic Poly(β-Amino ester) nanoparticle for highly efficient and specific delivery of nucleic acids to the Lung capillary endothelium

Endothelial cell dysfunction occurs in a variety of acute and chronic pulmonary diseases including pulmonary hypertension, viral and bacterial pneumonia, bronchopulmonary dysplasia, and congenital lung diseases such as alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV). To correct endothelial dysfunction, there is a critical need for the development of nanoparticle systems that can deliver drugs and nucleic acids to endothelial cells with high efficiency and precision. While several nanoparticle delivery systems targeting endothelial cells have been recently developed, none of them are specific to lung endothelial cells without targeting other organs in the body. In the present study, we successfully solved this problem by developing non-toxic poly(β-amino) ester (PBAE) nanoparticles with specific structure design and fluorinated modification for high efficiency and specific delivery of nucleic acids to the pulmonary endothelial cells. After intravenous administration, the PBAE nanoparticles were capable of delivering non-integrating DNA plasmids to lung microvascular endothelial cells but not to other lung cell types. IVIS whole body imaging and flow cytometry demonstrated that DNA plasmid were functional in the lung endothelial cells but not in endothelial cells of other organs. Fluorination of PBAE was required for lung endothelial cell-specific targeting. Hematologic analysis and liver and kidney metabolic panels demonstrated the lack of toxicity in experimental mice. Thus, fluorinated PBAE nanoparticles can be an ideal vehicle for gene therapy targeting lung microvascular endothelium in pulmonary vascular disorders.

Multifunctional properties of the transmembrane LPxTG-motif protein derived from Limosilactobacillus reuteri SH-23

The LPxTG-motif protein is an important transmembrane protein with high hydrophilicity and stability, as evidenced by its stress tolerance and adhesion ability. In this study, a novel LPxTG-motif protein with esterase activity (LEP) was expressed, and the multifunctional properties such as adhesion properties and esterase activity were also investigated. When cocultured with Limosilactobacillus reuteri SH-23, the adhesion ability of L. reuteri SH-23 to HT-29 cells was improved, and this adhesion was further found relating to the potential target protein Pyruvate kinase M1/2 (PKM) of HT-29 cells. In addition, as a multifunctional protein, LEP can promote the hydrolysis of bovine milk lipids with its esterase activity, and the activity was enhanced in the presence of Zn2+ and Mn2+ at pH 7. Furthermore, the polyunsaturated fatty acids (PUFA) such as linoleic acid and eicosapentaenoic acid were found to increase during the hydrolyzing process. These unique properties of LEP provide a comprehensive understanding of the adhesion function and PUFA releasing properties of the multifunctional protein derived from L. reuteri SH-23 and shed light on the beneficial effect of this Lactobacillus strain on the colonization of the gastrointestinal tract.

Carbon Dots-Biomembrane Interactions and Their Implications for Cellular Drug Delivery

The effect of carbon dots (CDs) on a model blayer membrane was studied as a means of comprehending their ability to affect cell membranes. Initially, the interaction of N-doped carbon dots with a biophysical liposomal cell membrane model was investigated by dynamic light scattering, z-potential, temperature-modulated differential scanning calorimetry, and membrane permeability. CDs with a slightly positive charge interacted with the surface of the negative-charged liposomes and evidence indicated that the association of CDs with the membrane affects the structural and thermodynamic properties of the bilayer; most importantly, it enhances the bilayer's permeability against doxorubicin, a well-known anticancer drug. The results, like those of similar studies that surveyed the interaction of proteins with lipid membranes, suggest that carbon dots are partially embedded in the bilayer. In vitro experiments employing breast cancer cell lines and human healthy dermal cells corroborated the findings, as it was shown that the presence of CDs in the culture medium selectively enhanced cell internalization of doxorubicin and, subsequently, increased its cytotoxicity, acting as a drug sensitizer.

Ultra-Small Nano-Assemblies as Tumor-Targeted and Renal Clearable Theranostic Agent for Photodynamic Therapy

It is a challenge to design photosensitizers to balance between the tumor-targeting enrichment for precise treatment and efficient clearance within a reasonable timescale for reducing side effects. Herein, an ultra-small nano-photosensitizer 1a with excellent tumor-specific accumulation and renal clearance is reported. It is formed from the self-assembly of compound 1 bearing three triethylene glycol (TEG) arms and two pyridinium groups in water. The positively charged surface with neutral TEG coating enables 1a to efficiently target the tumor, with the signal-to-background ratio reaching as high as 11.5 after tail intravenous injection. The ultra-small size of 1a with an average diameter of 5.6 nm allows its fast clearance through kidney. Self-assembly also endows 1a with an 18.2-fold enhancement of reactive oxygygen species generation rate compared to compound 1 in organic solution. Nano-PS 1a manifests an excellent photodynamic therapy efficacy on tumor-bearing mouse models. This work provides a promising design strategy of photosensitizers with renal clearable and tumor-targeting ability.

Dually stimulative single-chain polymeric nano lock with dynamic ligands for sensitive detection of circulating tumor cells

Circulating tumor cells (CTCs) are important markers for cancer diagnosis and monitoring. However, CTCs detection remains challenging due to their scarcity, where most of the detection methods are compromised by the loss of CTCs in pre-enrichment, and by the lack of universal antibodies for capturing different kinds of cancer cells. Herein, we report a single-chain based nano lock (SCNL) polymer incorporating dually stimulative dynamic ligands that can bind with a broad spectrum of cancer cells and CTCs overexpressing sialic acid (SA) with high sensitivity and selectivity. The high sensitivity is realized by the polymeric single chain structure and the multi-valent functional moieties, which improve the accessibility and binding stability between the target cells and the SCNL. The highly selective targeting of cancer cells is achieved by the dynamic and dually stimulative nano lock structures, which can be unlocked and functionalized upon simultaneous exposure to overexpressed SA and acidic microenvironment. We applied the SCNL to detecting cancer cells and CTCs in clinical samples, where the detection threshold of SCNL reached 4 cells/mL. Besides CTCs enumeration, the SCNL approach could also be extended to metastasis assessment through monitoring the expressing level of surface SA on cancer cells.

Inhaled Pro-Efferocytic Nanozymes Promote Resolution of Acute Lung Injury

Acute lung injury (ALI) is a significant contributor to the morbidity and mortality of sepsis. Characterized by uncontrolled inflammation and excessive inflammatory cells infiltration in lung, ALI has been exacerbated by impaired efferocytosis (clearance of apoptotic cells by macrophages). Through specific receptor recognition and activation of downstream signaling, efferocytic macrophages promote resolution of inflammation by efficiently engulfing dying cells, avoiding the consequent release of cellular inflammatory contents. Here, inspired by the intrinsic recovery mechanism of efferocytosis, an apoptotic cell membrane (ACM) coated antioxidant nanozyme (AOzyme) is engineered, thus obtaining an inhalable pro-efferocytic nanozyme (AOzyme@ACM). Notably, AOzyme@ACM can efficiently increase apoptotic cell removal by combing enhanced macrophages recognition of "eat me" signals through apoptotic body mimicking and scavenge of intracellular excessive reactive oxygen species (ROS), a significant barrier for efferocytosis. AOzyme@ACM can significantly inhibit inflammatory response, promote pro-resolving (M2) phenotype transition of macrophage, and alleviate ALI in endotoxemia mice compared with AOzyme group. By addressing the critical factor in the pathogenesis of sepsis-related ALI through restoring efferocytosis activity, the ACM-based antioxidant nanozyme in this study is envisioned to provide a promising strategy to treat this complex and challenging disease.

Circulating tumor cell isolation for cancer diagnosis and prognosis

Circulating tumor cells (CTCs) are tumor cells that shed from the primary tumor and intravasate into the peripheral blood circulation system responsible for metastasis. Sensitive detection of CTCs from clinical samples can serve as an effective tool in cancer diagnosis and prognosis through liquid biopsy. Current CTC detection technologies mainly reply on the biomarker-mediated platforms including magnetic beads, microfluidic chips or size-sensitive microfiltration which can compromise detection sensitivity due to tumor heterogeneity. A more sensitive, biomarker independent CTCs isolation technique has been recently developed with the surface-charged superparamagnetic nanoprobe capable of different EMT subpopulation CTC capture from 1 mL clinical blood. In this review, this new strategy is compared with the conventional techniques on biomarker specificity, impact of protein corona, effect of glycolysis on cell surface charge, and accurate CTC identification. Correlations between CTC enumeration and molecular profiling in clinical blood and cancer prognosis are provided for clinical cancer management.

Path-Dependent Anisotropic Colloidal Assembly of Magnetic Nanocomposite-Protein Complexes

Anisotropic self-assembly of nanoparticles (NPs) stems from the fine-tuning of their surface functionality and NP interaction. Strategies involving ligand interaction, protein interaction, and external stimulus have been developed. However, robust construction of monodispersed magnetic NPs to tens of microns of anisotropically aligned colloidal assembly triggered by adsorbed protein intermolecular interaction is yet to be elucidated. Here, we present the NP-protein interaction, magnetic force, and protein corona intermolecular interaction serially but independently induced path-dependent self-assembly of 100 nm Fe₃O₄@SiO₂ nanocomposites. Dynamic formation of the micron-sized anisotropic magnetic assembly was reproducibly realized in a continuous medium in a controllable manner. Formation of the primary globular clusters upon the unique NP-protein complexes with the help of ions acts as the prerequisite for the anisotropic colloidal assembly, followed by the magnetic force-driven pre-organization and protein intermolecular electrostatic interaction-mediated elongation. The protein concentration rather than the protein original structure plays a more pivotal role in the NP-protein interaction and subsequent colloidal assembly process. Two typical serum proteins fibrinogen and bovine serum albumin enable formation of the anisotropic colloidal assembly but with a different subtle morphology. Furthermore, the obtained micron-sized magnetic colloidal assembly can be dissociated rapidly by adding a negative electrolyte in the medium due to the interference in the NP-protein interaction. However, the self-assembly process can be recycled based on the dissociated colloidal assembly.

The impact of protein corona on the biological behavior of targeting nanomedicines

For successful translation of targeting nanomedicines from bench to bedside, it is vital to address their most common drawbacks namely rapid clearance and off-target accumulation. These complications evidently originate from a phenomenon called "protein corona (PC) formation" around the surface of targeting nanoparticles (NPs) which happens once they encounter the bloodstream and interact with plasma proteins with high collision frequency. This phenomenon endows the targeting nanomedicines with a different biological behavior followed by an unexpected fate, which is usually very different from what we commonly observe in vitro. In addition to the inherent physiochemical properties of NPs, the targeting ligands could also remarkably dictate the amount and type of adsorbed PC. As very limited studies have focused their attention on this particular factor, the present review is tasked to discuss the best simulated environment and latest characterization techniques applied to PC analysis. The effect of PC on the biological behavior of targeting NPs engineered with different targeting moieties is further discussed. Ultimately, the recent progresses in manipulation of nano-bio interfaces to achieve the most favorite therapeutic outcome are highlighted.

Dual Targeting with Cell Surface Electrical Charge and Folic Acid via Superparamagnetic Fe3O4@Cu2-xS for Photothermal Cancer Cell Killing

Simple Summary

There are two critical issues in cancer hyperthermia: (1) photothermal effect and (2) cancer cell targeting efficiency. While the former can be addressed by rendering the nano carriers with significant IR absorptions, the latter is dealt with using a novel dual-targeting strategy. In this study, the Fe₃O₄ nanoparticle was coated with a shell of Cu_2–xS; the resulting Fe₃O₄@Cu_2–xS exhibited strong IR absorption for enhanced photothermal cancer cell killing. The Fe₃O₄@Cu_2–xS nanoparticles are surface functionalized with amphiphilic polyethylenimine (LA-PEI) and Folic acid-TPGS (FA-TPGS) for two purposes: (1) the PEI surface coating renders the particles positively charged, enabling them to effectively bind with negatively-charged cancer cells for more intimate nano/bio contact resulting in much stronger cancer cell ablation; (2) the folic acid modification further increases the targeting efficiency via the folic receptors on the cancer cell surface. Dual-targeting with the surface electrical charge and the tumor-specific folic acid synergistically facilitates both passive and active targeting for significantly improved photothermal killing.

Abstract

A major challenge in cancer therapy is to achieve high cell targeting specificity for the highest therapeutic efficacy. Two major approaches have been shown to be quite effective, namely, (1) bio-marker mediated cell targeting, and (2) electrical charge driven cell binding. The former utilizes the tumor-specific moieties on nano carrier surfaces for active targeting, while the latter relies on nanoparticles binding onto the cancer cell surfaces due to differences in electrical charge. Cancer cells are known for their hallmark metabolic pattern: high rates of glycolysis that lead to negatively charged cell surfaces. In this study, the nanoparticles of Fe₃O₄@Cu_2–xS were rendered positively charged by conjugating their surfaces with different functional groups for strong electrostatic binding onto the negatively-charged cancer cells. In addition to the positively charged surfaces, the Fe₃O₄@Cu_2–xS nanoparticles were also modified with folic acid (FA) for biomarker-based cell targeting. The dual-targeting approach synergistically utilizes the effectiveness of both charge- and biomarker-based cell binding for enhanced cell targeting. Further, these superparamagnetic Fe₃O₄@Cu_2–xS nanoparticles exhibit much stronger IR absorptions compared to Fe₃O₄, therefore much more effective in photothermal therapy.

Development and Characterization of Fe3O4@Carbon Nanoparticles and Their Biological Screening Related to Oral Administration

The current study presents the effect of naked Fe3O4@Carbon nanoparticles obtained by the combustion method on primary human gingival fibroblasts (HGFs) and primary gingival keratinocytes (PGKs)-relevant cell lines of buccal oral mucosa. In this regard, the objectives of this study were as follows: (i) development via combustion method and characterization of nanosized magnetite particles with carbon on their surface, (ii) biocompatibility assessment of the obtained magnetic nanoparticles on HGF and PGK cell lines and (iii) evaluation of possible irritative reaction of Fe3O4@Carbon nanoparticles on the highly vascularized chorioallantoic membrane of a chick embryo. Physicochemical properties of Fe3O4@Carbon nanoparticles were characterized in terms of phase composition, chemical structure, and polymorphic and molecular interactions of the chemical bonds within the nanomaterial, magnetic measurements, ultrastructure, morphology, and elemental composition. The X-ray diffraction analysis revealed the formation of magnetite as phase pure without any other secondary phases, and Raman spectroscopy exhibit that the pre-formed magnetic nanoparticles were covered with carbon film, resulting from the synthesis method employed. Scanning electron microscopy shown that nanoparticles obtained were uniformly distributed, with a nearly spherical shape with sizes at the nanometric level; iron, oxygen, and carbon were the only elements detected. While biological screening of Fe3O4@Carbon nanoparticles revealed no significant cytotoxic potential on the HGF and PGK cell lines, a slight sign of irritation was observed on a limited area on the chorioallantoic membrane of the chick embryo.

Nanoscale photosensitizer with tumor-selective turn-on fluorescence and activatable photodynamic therapy treatment for COX-2 overexpressed cancer cells

Effective targeting and in situ imaging-guided treatment are particularly important for accurate clinical photodynamic therapy (PDT) of malignant tumors. Herein, we propose a single molecule, named IMC-DAH-SQ, which possesses dual-targeting components, including structure-inherent targeting (SIT) and cyclooxygenase-2 (COX-2) targeting units, and controllable turn-on near infrared (NIR) fluorescence. Due to its amphiphilicity, IMC-DAH-SQ assembles into a nanoprobe with low background fluorescence. After incubation with tumor cells, the SIT and COX-2 recognition characteristics of IMC-DAH-SQ endow it with preferential tumor-targeting activity. The strong binding with overexpressed COX-2 can collapse the nanoprobe to monomers after accumulation in tumor cells, leading to turn-on NIR fluorescence that is completely different from normal cells. Additionally, benefiting from the single molecular model tactic, the nanoprobe has the advantages of simple synthesis without ever considering the loading rate and separation between the photosensitizer and targeting unit. Other favorite features, including superior biocompatibility, weak dark toxicity, and mitochondria enrichment capability, are implemented. All these traits not only afford nanoprobe precision tumor cell targeting capability but also provide promising imaging-guided antitumor therapy. We believe that the single molecular protocol will establish a novel strategy for simultaneous diagnosis and anticancer medicine treatment utilizing versatile but small compounds.

Nanoparticle Delivery Systems with Cell-Specific Targeting for Pulmonary Diseases

Respiratory disorders are among the most important medical problems threatening human life. The conventional therapeutics for respiratory disorders are hindered by insufficient drug concentrations at pathological lesions, lack of cell-specific targeting, and various biobarriers in the conducting airways and alveoli. To address these critical issues, various nanoparticle delivery systems have been developed to serve as carriers of specific drugs, DNA expression vectors, and RNAs. The unique properties of nanoparticles, including controlled size and distribution, surface functional groups, high payload capacity, and drug release triggering capabilities, are tailored to specific requirements in drug/gene delivery to overcome major delivery barriers in pulmonary diseases. To avoid off-target effects and improve therapeutic efficacy, nanoparticles with high cell-targeting specificity are essential for successful nanoparticle therapies. Furthermore, low toxicity and high degradability of the nanoparticles are among the most important requirements in the nanoparticle designs. In this review, we provide the most up-to-date research and clinical outcomes in nanoparticle therapies for pulmonary diseases. We also address the current critical issues in key areas of pulmonary cell targeting, biosafety and compatibility, and molecular mechanisms for selective cellular uptake.

Nanomedicines: Redefining traditional medicine

Nanomedicines offer nanoscale drug delivery system. They offer ways of promising drug transportation, and address the issues of lack of targeting and permeability of traditional drugs. The physical and chemical properties in the domain of nanomedicine applications in vivo have not been sufficiently delivered. What's more, the metabolic of nanomedicines is not clear enough. Those factors which mentioned above determine that many nanomedicines have not yet realized clinical application due to their safety problems and in vivo efficacy. For example, they may cause immune response and cytotoxicity, as well as the ability to clear organs in vivo, the penetration ability of them and the lack of targeting ability may also cause poor efficacy of drugs in vivo. In this review, the new progresses of different kinds of nanomedicines (including gold nanoparticles, nanorobots, black phosphorus nanoparticles, brain diseases, gene editing and immunotherapy etc.) in anti-tumor, antibacterial, ocular diseases and arteriosclerosis in recent years were summarized. Their shortcomings were pointed out, and the new methods to improve the biosafety and efficacy were summarized.

Engineering at the nano-bio interface: harnessing the protein corona towards nanoparticle design and function

Unpredictable and uncontrollable protein adsorption on nanoparticles remains a considerable challenge to achieving effective application of nanotechnologies within biological environments. Nevertheless, engineered nanoparticles offer unprecedented functionality and control in probing and altering biological systems. In this review, we highlight recent advances in harnessing the "protein corona" formed on nanoparticles as a handle to tune functional properties of the protein-nanoparticle complex. Towards this end, we first review nanoparticle properties that influence protein adsorption and design strategies to facilitate selective corona formation, with the corresponding characterization techniques. We next focus on literature detailing corona-mediated functionalities, including stealth to avoid recognition and sequestration while in circulation, targeting of predetermined in vivo locations, and controlled activation once localized to the intended biological compartment. We conclude with a discussion of biocompatibility outcomes for these protein-nanoparticle complexes applied in vivo. While formation of the nanoparticle-corona complex may impede our control over its use for the projected nanobiotechnology application, it concurrently presents an opportunity to create improved protein-nanoparticle architectures by exploiting natural or guiding selective protein adsorption to the nanoparticle surface.

Positively Charged Magnetic Nanoparticles for Capture of Circulating Tumor Cells from Clinical Blood Samples

Isolation of circulating tumor cells (CTCs) from cancer patients is of high value for disease monitoring and metastasis diagnosis. Although many new detection methods have emerged in recent years, the detection of CTCs is a current challenge due to lack of specific and sensitive markers. In our previous work, cancer cell surfaces, from over 20 cancer cell lines, have been shown to be negatively-charged regardless of their phenotype by using electrically-charged nanoparticles as a probe. The strong electrostatic interaction between the negative cancer cells and positively charged nanoparticles can well remain in a physiological liquid environment in the presence of serum proteins, enabling effective binding between them. As a result, the cancer cells can be magnetically separated by employing an external magnet. In this technical report, we present preliminary results on the investigation of CTC isolation from both mimetic and clinical blood samples. We show high CTC detection sensitivity by the positively-charged magnetic nanoparticles (PMNs) even at the original concentration of 10 cells per mL mimetic blood sample. The CTCs in the peripheral blood of colorectal cancer patients were isolated and identified by cellular morphology and immunofluorescence staining.

Rapid Label-Free Isolation of Circulating Tumor Cells from Patients' Peripheral Blood Using Electrically Charged Fe3O4 Nanoparticles

Isolation of circulating tumor cells (CTCs) in peripheral blood from cancer patients bears critical importance for evaluation of therapeutic efficacy. The current CTC isolation strategies are majorly relying on either protein biomarkers or dimensional features of CTCs. In this study, we present a new methodology for CTC detection and isolation based on the surface charge of cancer cells, a bioelectrical manifestation of the "Warburg effect." Negative surface charge is a direct consequence of glycolysis of cancer cells, which can be utilized as an effective biophysical marker for CTC detection and isolation. Upon cancer cells-nanoparticle interaction via optimum incubation, serum protein-coated electrically charged nanoparticles can trap different cancer cells independent of their epithelial protein expression. In fetal bovine serum , the poly(ethyleneimine)-functionalized Fe₃O₄ nanoparticles, surface-decorated with protein corona, are able to efficiently capture CTCs from blood samples of colorectal cancer patients.  2-8 CTCs has been isolated from 1 mL of blood and identified by immunostaining fluorescence in situ hybridization and immunofluorescence staining in all 25 colorectal cancer patients at varied stages, while only 0-1 CTC was detected from blood samples of 10 healthy donors. Diverse CTC subpopulations of heteroploids and biomarker expression can also be detected in this strategy. The label-free, charge-based CTC method shows promise in cancer diagnosis and prognosis paving a new path for liquid biopsy.

Magnetic Nanoparticles for Nanomedicine

The field of nanomedicine has recently emerged as a product of the expansion of a range of nanotechnologies into biomedical science, pharmacology and clinical practice. Due to the unique properties of nanoparticles and the related nanostructures, their applications to medical diagnostics, imaging, controlled drug and gene delivery, monitoring of therapeutic outcomes, and aiding in medical interventions, provide a new perspective for challenging problems in such demanding issues as those involved in the treatment of cancer or debilitating neurological diseases. In this review, we evaluate the role and contributions that the applications of magnetic nanoparticles (MNPs) have made to various aspects of nanomedicine, including the newest magnetic particle imaging (MPI) technology allowing for outstanding spatial and temporal resolution that enables targeted contrast enhancement and real-time assistance during medical interventions. We also evaluate the applications of MNPs to the development of targeted drug delivery systems with magnetic field guidance/focusing and controlled drug release that mitigate chemotherapeutic drugs’ side effects and damage to healthy cells. These systems enable tackling of multiple drug resistance which develops in cancer cells during chemotherapeutic treatment. Furthermore, the progress in development of ROS- and heat-generating magnetic nanocarriers and magneto-mechanical cancer cell destruction, induced by an external magnetic field, is also discussed. The crucial roles of MNPs in the development of biosensors and microfluidic paper array devices (µPADs) for the detection of cancer biomarkers and circulating tumor cells (CTCs) are also assessed. Future challenges concerning the role and contributions of MNPs to the progress in nanomedicine have been outlined.

Multi-Stimuli-Responsive Polymeric Prodrug for Enhanced Cancer Treatment

Accomplishing efficient delivery of a nanomedicine to the tumor site will encounter two contradictions as follows: 1) a contradiction between prolonged circulation time and endocytosis by cancer cells; 2) a dilemma between the stability of nanomedicine during blood circulation and intracellular drug release. While developing a nanomedicine which can solve the above two contradictions simultaneously is still a challenge, here, a multi-stimuli-responsive polymeric prodrug (PLys-co-(PLys-DA)-co-(PLys-SS-PTX))-b-PLGLAG-mPEG (P-PEP-SS-PTX-DA) is synthesized which is multi-sensitive to overexpressed matrix metalloproteinase-2 (MMP-2), low pH, and high concentration of glutathione in tumors. The P-PEP-SS-PTX-DA can be dePEGylated and reversed from negative at normal physiological pH to positive charge at tumor extracellular microenvironment; in this way, it can solve the contradiction between prolonged circulation time and endocytosis by cancer cells. Owing to the high reductive conditions in cancer cells, P-PEP-SS-PTX-DA is ruptured to release paclitaxel (PTX) intracellular efficiently; therefore, it can resolve the dilemma between the stability of nanomedicine during blood circulation and intracellular drug release. These indicate that the multi-stimuli-responsive polymeric prodrug has potential application prospects in drug delivery and cancer therapy.

Molecular Programming of Biodegradable Nanoworms via Ionically Induced Morphology Switch toward Asymmetric Therapeutic Carriers

Engineering biodegradable nanostructures with precise morphological characteristics is a key objective in nanomedicine. In particular, asymmetric (i.e., nonspherical) nanoparticles are desirable due to the advantageous effects of shape in a biomedical context. Using molecular engineering, it is possible to program unique morphological features into the self-assembly of block copolymers (BCPs). However, the criteria of biocompatibility and scalability limit progress due to the prevalence of nondegradable components and the use of toxic solvents during fabrication. To address this shortfall, a robust strategy for the fabrication of morphologically asymmetric nanoworms, comprising biodegradable BCPs, has been developed. Modular BCPs comprising poly (ethylene glycol)-block-poly(caprolactone-gradient-trimethylene carbonate) (PEG-PCLgTMC), with a terminal chain of quaternary ammonium-TMC (PTMC-Q), undergo self-assembly via direct hydration into well-defined nanostructures. By controlling the solution ionic strength during hydration, particle morphology switches from spherical micelles to nanoworms (of varying aspect ratio). This ionically-induced switch is driven by modulation of chain packing with salts screening interchain repulsions, leading to micelle elongation. Nanoworms can be loaded with cytotoxic cargo (e.g., doxorubicin) at high efficiency, preferentially interact with cancer cells, and increase tumor penetration. This work showcases the ability to program assembly of BCPs and the potential of asymmetric nanosystems in anticancer drug delivery.

Bioelectricity, Its Fundamentals, Characterization Methodology, and Applications in Nano-Bioprobing and Cancer Diagnosis

Bioelectricity is an essential characteristic of a biological system that has played an important role in medical diagnosis particularly in cancer liquid biopsy. However, its biophysical origin and measurements have presented great challenges in experimental methodologies. For instance, in dynamic cell processes, bioelectricity cannot be accurately determined as a static electrical potential via electrophoresis. Cancer cells fundamentally differ from normal cells by having a much higher rate of glycolysis resulting in net negative charges on cell surfaces. The most recent investigations on cancer cell surface charge that is the direct bio-electrical manifestation of the "Warburg Effect," which can be directly monitored by specially designed nanoprobes, has been provided. The most up-to-date research results from charge-mediated cell targeting are reviewed. Correlations between the cell surface charge and cancer cell metabolism are established based on cell/probe electrostatic interactions. Bioelectricity is utilized not only as an analyte for investigation of the metabolic state of the cancer cells, but also applied in electrostatically and magnetically capturing of the circulating tumor cells from whole blood. Also reviewed is on the isolation of Candida albicans via bioelectricity-driven nanoparticle binding on fungus with surface charges.

Preparation of a Novel Raman Probe and Its Application in the Detection of Circulating Tumor Cells and Exosomes

The Raman probe plays an essential role in sensitive surface-enhanced Raman scattering (SERS) assay. Here, a novel Raman probe was developed by assembling gold nanoparticles in triangular pyramid DNA (TP-Au NPs). Such probe with intense electromagnetic hot spots can provide dramatically enhanced Raman scattering. Through assembling recognition DNA on one corner of the TP-DNA, the recognition event is definite and designable. The probe was characterized through TEM, and its SERS superiority was investigated. As models, circulating tumor cells and exosomes were detected with high sensitivity and selectivity by using this probe. Meanwhile, the developed SERS probe can also perform well in real world samples.

Preparation of Colloidally Stable Positively Charged Hollow Silica Nanoparticles: Effect of Minimizing Hydrolysis on ζ Potentials

Silica nanoparticles have received great attention as versatile nanomaterials in many fields such as drug delivery, sensing, and imaging due to their physical and chemical flexibility. Specifically, the silanol groups at the surface of silica nanoparticles have enabled various surface modifications and functionalization to tailor the nanoparticles for each application. Chemical tailoring to switch from negative to positive surface charge has been one important strategy to enhance cell internalization and biodistribution of the nanoparticles. However, efficient surface charge modification that is sustained upon dispersion is difficult to achieve and has not been well characterized though it can be a critical requirement for successful nanoparticle performance. In this study, solid spherical silica nanoparticles and hollow spherical silica nanoparticles around 45 nm in diameter were synthesized, both possessing tunable positive ζ potentials in aqueous colloidal suspension, to investigate the relationship between time-dependent ζ potential changes and their morphologies. A set of three different particles showing varied ζ potentials of approximately 5, 20, and >30 mV in both morphologies were prepared, and their colloidal surface electric potential fluctuations were measured. These studies reveal that the hollow morphologies are much more effectively able to maintain positive ζ potentials for 7 days of aqueous incubation, whereas the magnitude of the ζ potential of the solid silica spheres decreases uncontrollably, largely due to hydrolysis of the interior siloxane bonds, resulting in adsorption of the released silicic acid onto the nanoparticle surface.

Nanovector-Mediated Drug Delivery in Spinal Cord Injury: A Multitarget Approach

Many preclinical studies seek cures for spinal cord injury (SCI), but when the results are translated to clinical trials they give scant efficacy. One possible reason is that most strategies use treatments directed toward a single pathological mechanism, while a multitherapeutic approach needs to be tested to significantly improve outcomes after SCI. Most of the preclinical reports gave better outcomes when a combination of different compounds was used instead of a single drug. This promising approach, however, must still be improved because it raises some criticism: (i) the blood-spinal cord barrier limits drug distribution, (ii) it is hard to understand the interactions among the pharmacological components after systemic administration, and (iii) the timing of treatments is crucial: the spread of the lesion is a process finely regulated over time, so therapies must be scheduled at precise times during the postinjury course. Nanomedicine could be useful to overcome these limitations. Nanotools allow finely regulated drug administration in terms of cell selectivity and release kinetics. We believe that excellent therapeutic results could be obtained by exploiting this tool in multitherapy. Combining nanoparticles loaded with different compounds that act on the main pathological pathways could overcome the restrictions of traditional drug delivery routes, a major limit for the clinical application of multitherapy. This review digs into these topics, discussing the critical aspects of multitherapies now proposed and suggesting new points of view.

Cancer cell–nanomaterial interface: role of geometry and surface charge of nanocomposites in the capture efficiency and cell viability

The nanomaterial–cell interface plays an important role in biodetection and therapy. The experimental results in this study indicated that the magnetic nanocomposites with strong positive surface charge but different geometry interacted with cancer cells in different ways, leading to various cell capture efficiency and cytotoxicity.