Polydopamine nanoparticles carrying tumor cell lysate as a potential vaccine for colorectal cancer immunotherapy

β-Glucan-A promising immunocyte-targeting drug delivery vehicle: Superiority, applications and future prospects

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, β-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, β-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of β-glucans applied in the drug delivery system including yeast β-glucan, Schizophyllan and curdlan, highlighting the benefits of β-glucan based delivery system. We summarize how β-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of β-glucan based delivery systems.

Uplifting Antitumor Immunotherapy with Lymph-Node-Targeted and Ratio-Controlled Codelivery of Tumor Cell Lysate and Adjuvant

Cancer vaccines provide a potential strategy to cure patients. Their clinical utilization and efficacy is, however, limited by incomplete coverage of tumor neoantigens and unspecific and restricted activation of dendritic cells (DCs). Tumor cell lysates (TCLs) containing a broad spectrum of neoantigens, while are considered ideal in formulating personalized vaccines, induce generally poor antigen presentation and transient antitumor immune response. Here, intelligent polymersomal nanovaccines (PNVs) that quantitatively coload, efficiently codeliver, and responsively corelease TCL and CpG adjuvant to lymph node (LN) DCs are developed to boost antigen presentation and to induce specific and robust antitumor immunity. PNVs carrying CpG and ovalbumin (OVA) markedly enhance the maturation, antigen presentation, and downstream T cell activation ability of bone-marrow-derived dendritic cells and induce strong systemic immune response after tail base injection. Remarkably, PNVs carrying CpG and TCL cure 85% of B16-F10 melanoma-bearing mice and generate long-lasting anticancer immune memory at a low dose, protecting all cured mice from tumor rechallenge. These LN-directed PNVs being highly versatile and straightforward opens a new door for personalized cancer vaccines.

Toward nano-sized imprinted norepinephrine-derived biopolymer as artificial receptors for detecting IgG1 by surface plasmon resonance

Bio-based nanostructured molecularly imprinted polymers (nano-MIPs), also known as 'plastibodies', have a real potential to be used as alternatives to natural antibodies. These nanostructures have recently gained significant attention for diagnostic and therapeutic purposes. In this context, we have developed polynorepinephrine (PNE)-based nano-MIPs using an eco-friendly one-pot process for the sensitive and selective detection of a model biomolecule, immunoglobulin IgG1. We first investigated non-imprinted nanostructures (nano-NIPs) based on polydopamine as reference material, using DLS, SEM, and UV-Vis spectroscopy. Subsequently, PNE scaffolds were characterized, both in the form of nano-NIPs and nano-MIPs. Concerning nano-MIPs, we used the epitope-directed imprinting technology to create binding cavities using a small peptide from the constant region of IgG1 as a template. Nano-MIPs were initially immobilized on a sensing surface to assess their binding capacity via surface plasmon resonance (SPR) spectroscopy. This strategy showed very good sensitivity, outperforming planar PNE-based imprinted films while keeping a high selectivity even in complex biological matrices such as human serum. Furthermore, we confirmed the presence of selective binding sites on nano-MIPs by flowing them, along with nano-NIPs, through a microfluidic SPR system, where they interact with the covalently immobilized analyte. This approach resulted in a good imprinting factor of 4.5. Overall, this study underscores the broad potential of these nanostructures as a viable and reusable alternative to antibodies across a variety of bioanalytical, biochemical, and immunohistochemistry analysis techniques.

Liposome Nanomedicine Based on Tumor Cell Lysate Mitigates the Progression of Lynch Syndrome-Associated Colon Cancer

Treatment with immune checkpoint inhibitors (ICIs) has shown efficacy in some patients with Lynch syndrome-associated colon cancer, but some patients still do not benefit from it. In this study, we adopted a combination strategy of tumor vaccines and ICIs to maximize the benefits of immunotherapy. Here, we obtained tumor-antigen-containing cell lysate (TCL) by lysing MC38Mlh1 KD cells and prepared liposome nanoparticles (Lipo-PEG) with a typical spherical morphology by thin-film hydration. Anti-PD-L1 was coupled to the liposome surface by the amidation reaction. As observed, anti-PD-L1/TCL@Lipo-PEG was not significantly toxic to mouse intestinal epithelial cells (MODE-K) in the safe concentration range and did not cause hemolysis of mouse red blood cells. In addition, anti-PD-L1/TCL@Lipo-PEG reduced immune escape from colon cancer cells (MC38Mlh1 KD) by the anti-PD-L1 antibody, restored the killing function of CD8+ T cells, and targeted more tumor antigens to bone marrow-derived dendritic cells (BMDCs), which also expressed PD-L1, to stimulate BMDC antigen presentation. In syngeneic transplanted Lynch syndrome-associated colon cancer mice, the combination of anti-PD-L1 and TCL provided better cancer suppression than monoimmunotherapy, and the cancer suppression effect of anti-PD-L1/TCL@Lipo-PEG treatment was even better than that of the free drug. Meanwhile anti-PD-L1/TCL@Lipo-PEG enhanced the immunosuppressive tumor microenvironment. In vivo fluorescence imaging and H&E staining showed that the nanomedicine was mainly retained in the tumor site and had no significant toxic side effects on other major organs. The anti-PD-L1/TCL@Lipo-PEG prepared in this study has high efficacy and good biosafety in alleviating the progression of Lynch syndrome-associated colon cancer, and it is expected to be a therapeutic candidate for Lynch syndrome-associated colon cancer.

Polydopamine-based nano adjuvant as a promising vaccine carrier induces significant immune responses against Acinetobacter baumannii-associated pneumonia

The objective of this study was to assess the effectiveness of polydopamine nanoparticles (PDANPs) as a delivery system for intranasal antigen administration to prevent Acinetobacter baumannii (A. baumannii)-associated pneumonia. In the in vitro phase, the conserved outer membrane protein 22 (Omp22)-encoding gene of A. baumannii was cloned, expressed, and purified, resulting in the production of recombinant Omp22 (rOmp22), which was verified using western blot. PDANPs were synthesized using dopamine monomers and loaded with rOmp22 through physical adsorption. The rOmp22-loaded PDANPs were characterized in terms of size, size distribution, zeta potential, field emission scanning electron microscopy (FESEM), loading capacity, Fourier transform infrared spectroscopy (FTIR), release profile, and cytotoxicity. In the in vivo phase, the adjuvant effect of rOmp22-loaded PDANPs was evaluated in terms of eliciting immune responses, including humoral and cytokine levels (IL-4, IL-17, and IFN-γ), as well as protection challenge. The rOmp22-loaded PDANPs were spherical with a size of 205 nm, a zeta potential of -14 mV, and a loading capacity of approximately 35.7 %. The released rOmp22 from nontoxic rOmp22-loaded PDANPs over 20 days was approximately 41.5 %, with preserved rOmp22 integrity. The IgG2a/IgG1 ratio and IFN-γ levels were significantly higher in immunized mice with rOmp22-loaded-PDANPs than in rOmp22-alum, naive Omp22, and control groups. Furthermore, rOmp22-loaded PDANPs induced effective protection against infection in the experimental challenge and showed more normal structures in the lung histopathology assay. The results of this study suggest the potential of PDANPs as a nano-adjuvant for inducing strong immune responses to combat A. baumannii.

Nanovaccines: An effective therapeutic approach for cancer therapy

Cancer vaccines hold considerable promise for the immunotherapy of solid tumors. Nanomedicine offers several strategies for enhancing vaccine effectiveness. In particular, molecular or (sub) cellular vaccines can be delivered to the target lymphoid tissues and cells by nanocarriers and nanoplatforms to increase the potency and durability of antitumor immunity and minimize negative side effects. Nanovaccines use nanoparticles (NPs) as carriers and/or adjuvants, offering the advantages of optimal nanoscale size, high stability, ample antigen loading, high immunogenicity, tunable antigen presentation, increased retention in lymph nodes, and immunity promotion. To induce antitumor immunity, cancer vaccines rely on tumor antigens, which are administered in the form of entire cells, peptides, nucleic acids, extracellular vesicles (EVs), or cell membrane-encapsulated NPs. Ideal cancer vaccines stimulate both humoral and cellular immunity while overcoming tumor-induced immune suppression. Herein, we review the key properties of nanovaccines for cancer immunotherapy and highlight the recent advances in their development based on the structure and composition of various (including synthetic and semi (biogenic) nanocarriers. Moreover, we discuss tumor cell-derived vaccines (including those based on whole-tumor-cell components, EVs, cell membrane-encapsulated NPs, and hybrid membrane-coated NPs), nanovaccine action mechanisms, and the challenges of immunocancer therapy and their translation to clinical applications.

Tumor Cell Lysate-Based Multifunctional Nanoparticles Facilitate Enhanced mRNA Delivery and Immune Stimulation for Melanoma Gene Therapy

Messenger ribonucleic acid (mRNA)-based gene therapy has great potential for cancer gene therapy. However, the effectiveness of mRNA in cancer therapy needs to be further improved, and the delivery efficiency and instability of mRNA limit the application of mRNA-based products. Both the delivery efficiency can be elevated by cell-penetrating peptide modification, and the immune response can be enhanced by tumor cell lysate stimulation, representing an advantageous strategy to expand the effectiveness of mRNA gene therapy. Therefore, it is vital to exploit a vector that can deliver high-efficiency mRNA with codelivery of tumor cell lysate to induce specific immune responses. We previously reported that DMP cationic nanoparticles, formed by the self-assembly of DOTAP and mPEG-PCL, can deliver different types of nucleic acids. DMP has been successfully applied in gene therapy research for various tumor types. Here, we encapsulated tumor cell lysates with DMP nanoparticles and then modified them with a fused cell-penetrating peptide (TAT-iRGD) to form an MLSV system. The MLSV system was loaded with encoded Bim mRNA, forming the MLSV/Bim complex. The average size of the synthesized MLSV was 191.4 nm, with a potential of 47.8 mV. The MLSV/mRNA complex promotes mRNA absorption through caveolin-mediated endocytosis, with a transfection rate of up to 68.6% in B16 cells. The MLSV system could also induce the maturation and activation of dendritic cells, obviously promoting the expression of CD80, CD86, and MHC-II both in vitro and in vivo. By loading the encoding Bim mRNA, the MLSV/Bim complex can inhibit cell proliferation and tumor growth, with inhibition rates of up to 87.3% in vitro. Similarly, the MLSV/Bim complex can inhibit tumor growth in vivo, with inhibition rates of up to 78.7% in the B16 subcutaneous tumor model and 63.3% in the B16 pulmonary metastatic tumor model. Our results suggest that the MLSV system is an advanced candidate for mRNA-based immunogene therapy.

Efficient Colon Cancer Immunogene Therapy Through Co-Delivery of IL-22BP mRNA and Tumor Cell Lysate by CLSV Nanoparticles

Background

Messenger ribonucleic acid (mRNA)-based gene therapy has great potential in cancer treatment. However, the application of mRNA-based cancer treatment could be further developed. Elevated delivery ability and enhanced immune response are advantages for expanding the application of mRNA-based cancer therapy. It is crucial that the prepared carrier can cause an immune reaction based on the efficient delivery of mRNA.

Methods

We reported DMP nanoparticle previously, which was obtained by the self-assembly of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) and (ethylene glycol)-b-poly (ε-caprolactone) (mPEG-PCL). Research demonstrated that DMP can deliver mRNA, siRNA, and plasmid. And it is applied to various tumor types. In our work, the tumor cell lysate was introduced to the internal DMP chain, fusing cell-penetrating peptides (CPPs) modification on the surface forming the CLSV system. And then mixed encoded IL-22BP (interleukin-22 binding protein) mRNA and CLSV to form CLSV/IL-22BP complex.

Results

The size of the CLSV system was 213.2 nm, and the potential was 45.7 mV. The transfection efficiency of the CLSV system is up to 76.45% in C26 cells via the micropinocytosis pathway. The CLSV system also could induce an immune response and significantly elevate the expression of CD80, CD86, and MHC-II in vivo. Then, by binding with IL-22BP (Interleukin-22 binding protein) mRNA, the CLSV/IL-22BP complex inhibited tumor cell growth, with an inhibition rate of up to 82.3% in vitro. The CLSV/IL-22BP complex also inhibited tumor growth in vivo, the tumor cell growth inhibition up to 75.0% in the subcutaneous tumor model, and 84.9% in the abdominal cavity metastasis tumor model.

Conclusion

Our work demonstrates that the CLSV system represents a potent potential for mRNA delivery.

Tumor-derived systems as novel biomedical tools-turning the enemy into an ally

Cancer is a complex illness that presents significant challenges in its understanding and treatment. The classic definition, "a group of diseases characterized by the uncontrolled growth and spread of abnormal cells in the body," fails to convey the intricate interaction between the many entities involved in cancer. Recent advancements in the field of cancer research have shed light on the role played by individual cancer cells and the tumor microenvironment as a whole in tumor development and progression. This breakthrough enables the utilization of the tumor and its components as biological tools, opening new possibilities. This article delves deeply into the concept of "tumor-derived systems", an umbrella term for tools sourced from the tumor that aid in combatting it. It includes cancer cell membrane-coated nanoparticles (for tumor theranostics), extracellular vesicles (for tumor diagnosis/therapy), tumor cell lysates (for cancer vaccine development), and engineered cancer cells/organoids (for cancer research). This review seeks to offer a complete overview of the tumor-derived materials that are utilized in cancer research, as well as their current stages of development and implementation. It is aimed primarily at researchers working at the interface of cancer biology and biomedical engineering, and it provides vital insights into this fast-growing topic.

Targeted siRNA Delivery by Bioinspired Cancer Cell Membrane-Coated Nanoparticles with Enhanced Anti-Cancer Immunity

Introduction

Cell-membrane nanocarriers are usually constructed by modifying the nanoparticle surface with cell membrane extracts, which has a direct benefit in endowing targeting capacity to nanocarriers based on their original cell types. However, delivering nucleic acid cargos by cell membrane-based nanoparticles is difficult owing to the strong negative charge of the cell membrane fraction. In this study, we developed a cancer cell membrane-based drug delivery system, the cMDS, for efficient siRNA delivery. Meanwhile, the cancer-specific immune response stimulated by the gene vector itself could offer synergistic anti-cancer ability.

Methods

The cMDS was prepared by ultrasound, and its transfection efficiency and anti-cancer ability were examined using cultures of CT26 cells. MTT and red blood cell hemolysis tests were performed to assess the safety of cMDS, while its targeted gene delivery and strong immune stimulation were investigated in a subcutaneous tumor model. Moreover, the detailed anti-cancer immune stimulation mechanisms of cMDS are uncovered by protein chip analysis.

Results

The cMDS was spherical core-shell structure. It showed high transfection efficiency and anti-cancer ability in vitro. In animal experiments, intravenously administered cMDS/siStat3 complex efficiently suppress the growth of colon cancer. Moreover, the result of protein chip analysis suggested that cMDS affect the migration and chemotaxis of immune cells.

Conclusion

The cMDS shows obvious tumor tissue-specific accumulation properties and strong immune stimulation ability. It is an advanced targeted gene delivery system with potent immunotherapeutic properties.

Cloaking Mesoporous Polydopamine with Bacterial Membrane Vesicles to Amplify Local and Systemic Antitumor Immunity

As adjuvants or antigens, bacterial membranes have been widely used in recent antibacterial and antitumor research, but they are often injected multiple times to achieve therapeutic outcomes, with limitations in biosafety and clinical application. Herein, we leverage the biocompatibility and immune activation capacity of Salmonella strain VNP20009 to produce double-layered membrane vesicles (DMVs) for enhanced systemic safety and antitumor immunity. Considering the photothermal effect of polydopamine upon irradiation, VNP20009-derived DMVs are prepared to coat the surface of mesoporous polydopamine (MPD) nanoparticles, leading to the potential synergies between photothermal therapy mediated by MPD and immunotherapy magnified by DMVs. The single dose of MPD@DMV can passively target tumors and activate the immune system with upregulated T cell infiltration and secretion levels of pro-inflammatory factors as well as antitumor related cytokines. All of these promoted immune responses result in malignant melanoma tumor regression and extended survival time on local or distant tumor-bearing mouse models. Importantly, we further explore the advantages of intravenous injection of the MPD@DMV agent compared with its intratumoral injection, and the former demonstrates better long-term immune effects on animal bodies. Overall, this formulation design brings broader prospects for the autologous vaccine adjuvant by bacterial membrane vesicles in cancer therapy.

Comparison of tumor-derived total RNA and cell lysate on antitumor immune activity

Tumor-derived total RNA (TdRNA) and cell lysate (TCL), with almost all the relevant tumor antigens, represent attractive alternative sources of antigens in antitumor immunotherapy. However, the comparison of their capacity to elicit immune responses against breast cancer is still lacking. In this study, the antitumor immune effects of TdRNA and TCL were systematically compared. We isolated TdRNA and TCL from 4T1 mouse breast cancer cells, and found that both sources of antigens could stimulate the maturation of dendritic cells (DCs) at the cellular and in vivo levels, and induce robust cellular immune responses, as evidenced by the increased percentages of both CD4⁺ and CD8⁺ T cells in the inguinal lymph nodes and spleen. But TdRNA performed stronger immunoactivities than TCL on the increase of T cell population through DCs activation. Additionally, the synergistic antitumor efficacy of paclitaxel (PTX) with TdRNA and TCL respectively was further evaluated in the murine 4T1 tumor model. Compared with TCL, TdRNA could inhibit tumor growth more effectively with low systemic toxicity when combined with PTX, which was, at least in part, attributable to the improvement of systemic immune function and tumor immune infiltration. Overall, TdRNA outperforms TCL in antitumor immunity, and is expected to be a promising candidate for application as the source of tumor antigens.

Tumor-Antigen Activated Dendritic Cell Membrane-Coated Biomimetic Nanoparticles with Orchestrating Immune Responses Promote Therapeutic Efficacy against Glioma

Immunotherapy has had a profound positive effect on certain types of cancer but has not improved the outcomes of glioma because of the blood-brain barrier (BBB) and immunosuppressive tumor microenvironment. In this study, we developed an activated mature dendritic cell membrane (aDCM)-coated nanoplatform, rapamycin (RAPA)-loaded poly(lactic-co-glycolic acid) (PLGA), named aDCM@PLGA/RAPA, which is a simple, efficient, and individualized strategy to cross the BBB and improve the immune microenvironment precisely. In vitro cells uptake and the transwell BBB model revealed that the aDCM@PLGA/RAPA can enhance homotypic-targeting and BBB-crossing efficiently. According to the in vitro and in vivo immune response efficacy of aDCM@PLGA/RAPA, the immature dendritic cells (DCs) could be stimulated into the matured status, which leads to further activation of immune cells, such as tumor-infiltrating T cells and natural killer cells, and can induce the subsequent immune responses through direct and indirect way. The aDCM@PLGA/RAPA treatment can not only inhibit glioma growth significantly but also has favorable potential ability to induce glial differentiation in the orthotopic glioma. Moreover, the aDCM@PLGA could induce a robust CD8⁺ effector and therefore suppress orthotopic glioma growth in a prophylactic setup, which indicates certain tumor immunity. Overall, our work provides an effective antiglioma drug delivery system which has great potential for tumor combination immunotherapy.

Engineered tumor cell-derived vaccines against cancer: The art of combating poison with poison

Tumor vaccination is a promising approach for tumor immunotherapy because it presents high specificity and few side effects. However, tumor vaccines that contain only a single tumor antigen can allow immune system evasion by tumor variants. Tumor antigens are complex and heterogeneous, and identifying a single antigen that is uniformly expressed by tumor cells is challenging. Whole tumor cells can produce comprehensive antigens that trigger extensive tumor-specific immune responses. Therefore, tumor cells are an ideal source of antigens for tumor vaccines. A better understanding of tumor cell-derived vaccines and their characteristics, along with the development of new technologies for antigen delivery, can help improve vaccine design. In this review, we summarize the recent advances in tumor cell-derived vaccines in cancer immunotherapy and highlight the different types of engineered approaches, mechanisms, administration methods, and future perspectives. We discuss tumor cell-derived vaccines, including whole tumor cell components, extracellular vesicles, and cell membrane-encapsulated nanoparticles. Tumor cell-derived vaccines contain multiple tumor antigens and can induce extensive and potent tumor immune responses. However, they should be engineered to overcome limitations such as insufficient immunogenicity and weak targeting. The genetic and chemical engineering of tumor cell-derived vaccines can greatly enhance their targeting, intelligence, and functionality, thereby realizing stronger tumor immunotherapy effects. Further advances in materials science, biomedicine, and oncology can facilitate the clinical translation of tumor cell-derived vaccines.

Synergy of Polydopamine Nanovaccine and Endostar Alginate Hydrogel for Improving Antitumor Immune Responses Against Colon Tumor

BACKGROUND

Tumor immunotherapy, a novel type of therapeutic treatment, has a wide range of applications with potentially prolonged benefits. However, current immunotherapy has a low overall response rate in treating a variety of tumors. Combination of immunotherapy with other therapies can improve the therapeutic response rates. The purpose of this work was to explore the potential of anti-angiogenic treatment in combination with tumor cell lysate loaded polydopamine nanoparticle vaccine as a therapeutic strategy for colon tumor.

METHODS

We grafted tumor cell lysate onto polydopamine nanoparticles as nano-vaccine (TCLN) and fabricated alginate hydrogel loaded with Endostar (EH), then detected characteristics of EH and TCLN. We also estimated the cytotoxicity of EH/TCLN in vitro. In the tumor-bearing mouse model, we evaluated the antitumor effect of EH/TCLN treatment, and developed the animal survival study. After performing the EH/TCLN treatment, we also analyzed T cells and DCs using flow cytometry, and determined T cell responses and tumor microenvironmental cytokines. At last, we assessed the effect of the EH/TCLN treatment on anti-angiogenesis further.

RESULTS

When applied in combination with TCLN in MC-38 tumor-bearing mice, EH/TCLN significantly suppressed tumor growth with more than half of the mice showing tumor regression. In addition, EH/TCLN treatment resulted in noticeable changes in the tumor microenvironment. As compared with the control group, EH/TCLN treatment led to significantly reduced tumor angiogenesis and expression of tumor microenvironment-related cytokines (TMCs), increased proportion of CD8⁺ T cells in the spleen, lymph node and tumor, elevated activity of cytotoxic T lymphocytes (CTLs) and tumor cell apoptosis.

CONCLUSION

The present study demonstrated that the EH/TCLN treatment effectively created a favorable immune microenvironment for the induction of antitumor immunity and improved antitumor immune responses.

Engineered nanomedicines for augmenting the efficacy of colorectal cancer immunotherapy

Colorectal cancer (CRC) is one of the most devastating diseases worldwide. Immunotherapeutic agents for CRC treatment have shown limited efficacy due to the immunosuppressive tumor microenvironment (TME). In this context, various types of nanoparticles (NPs) have been used to reverse the immunosuppressive TME, potentiate the effect of immunotherapeutic agents and reduce their systemic side effects. Many advantages could be offered by NPs, related to drug-loading efficiency, particle size and others that can potentially aid the delivery of immunotherapeutic agents. The recent research on how nano-based immunotherapy can remodel the immunosuppressive TME of CRC and hence boost the antitumor immune response, as well as the challenges that face clinical translation of NPs and future perspectives, are summarized in this review article.

Activation of Cellular Players in Adaptive Immunity via Exogenous Delivery of Tumor Cell Lysates

Tumor cell lysates (TCLs) are a good immunogenic source of tumor-associated antigens. Since whole necrotic TCLs can enhance the maturation and antigen-presenting ability of dendritic cells (DCs), multiple strategies for the exogenous delivery of TCLs have been investigated as novel cancer immunotherapeutic solutions. The TCL-mediated induction of DC maturation and the subsequent immunological response could be improved by utilizing various material-based carriers. Enhanced antitumor immunity and cancer vaccination efficacy could be eventually achieved through the in vivo administration of TCLs. Therefore, (1) important engineering methodologies to prepare antigen-containing TCLs, (2) current therapeutic approaches using TCL-mediated DC activation, and (3) the significant sequential mechanism of DC-based signaling and stimulation in adaptive immunity are summarized in this review. More importantly, the recently reported developments in biomaterial-based exogenous TCL delivery platforms and co-delivery strategies with adjuvants for effective cancer vaccination and antitumor effects are emphasized.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Melanin and Melanin-Functionalized Nanoparticles as Promising Tools in Cancer Research-A Review

Cancer poses an ongoing global challenge, despite the substantial progress made in the prevention, diagnosis, and treatment of the disease. The existing therapeutic methods remain limited by undesirable outcomes such as systemic toxicity and lack of specificity or long-term efficacy, although innovative alternatives are being continuously investigated. By offering a means for the targeted delivery of therapeutics, nanotechnology (NT) has emerged as a state-of-the-art solution for augmenting the efficiency of currently available cancer therapies while combating their drawbacks. Melanin, a polymeric pigment of natural origin that is widely spread among many living organisms, became a promising candidate for NT-based cancer treatment owing to its unique physicochemical properties (e.g., high biocompatibility, redox behavior, light absorption, chelating ability) and innate antioxidant, photoprotective, anti-inflammatory, and antitumor effects. The latest research on melanin and melanin-like nanoparticles has extended considerably on many fronts, allowing not only efficient cancer treatments via both traditional and modern methods, but also early disease detection and diagnosis. The current paper provides an updated insight into the applicability of melanin in cancer therapy as antitumor agent, molecular target, and delivery nanoplatform.

Inhibition of tumor recurrence and metastasis via a surgical tumor-derived personalized hydrogel vaccine

Tumor recurrence and metastasis have become thorny problems in clinical tumor therapy. Vaccine-mediated antitumor immune response has emerged as a significant postoperative inhibition for tumor recurrence and metastasis. However, limited tumor antigens are not conducive to trigger complete antigen-specific T cell-mediated immune responses. Herein, the design of a hydrogel vaccine system containing a granulocyte-macrophage colony stimulating factor (GM-CSF), based on surgically removed tumor cell lysates, was reported. The hydrogel was formed by crosslinking tumor cell lysates and alginate at low temperatures. The GM-CSF was released from the hydrogel to recruit dendritic cells (DCs), which provided a completely personalized tumor antigen pool. They were combined to foster the production of powerful antigen-specific T cells. The personalized hydrogel was implanted at the surgical site and it stimulated the antitumor immune response for the inhibition of residual tumor cells. Delightfully, the personalized hydrogel inhibited the tumor recurrence and metastasis well in a post-surgical mice tumor model, in combination with a programmed death-ligand 1 antibody (αPD-L1). The results demonstrated that the development of a personalized hydrogel and a combination of αPD-L1 provided a new strategy to prevent tumor recurrence and metastasis.

Symphony of nanomaterials and immunotherapy based on the cancer-immunity cycle

The immune system is involved in the initiation and progression of cancer. Research on cancer and immunity has contributed to the development of several clinically successful immunotherapies. These immunotherapies often act on a single step of the cancer–immunity cycle. In recent years, the discovery of new nanomaterials has dramatically expanded the functions and potential applications of nanomaterials. In addition to acting as drug-delivery platforms, some nanomaterials can induce the immunogenic cell death (ICD) of cancer cells or regulate the profile and strength of the immune response as immunomodulators. Based on their versatility, nanomaterials may serve as an integrated platform for multiple drugs or therapeutic strategies, simultaneously targeting several steps of the cancer–immunity cycle to enhance the outcome of anticancer immune response. To illustrate the critical roles of nanomaterials in cancer immunotherapies based on cancer–immunity cycle, this review will comprehensively describe the crosstalk between the immune system and cancer, and the current applications of nanomaterials, including drug carriers, ICD inducers, and immunomodulators. Moreover, this review will provide a detailed discussion of the knowledge regarding developing combinational cancer immunotherapies based on the cancer–immunity cycle, hoping to maximize the efficacy of these treatments assisted by nanomaterials.

Tumor Antigen-Based Nanovaccines for Cancer Immunotherapy: A Review

As an important means of tumor immunotherapy, tumor vaccines have achieved exciting results in the past few decades. However, there are still many obstacles that hinder tumor vaccines from achieving maximum efficacy, including lack of tumor antigens, low antigen immunogenicity and poor delivery efficiency. To overcome these challenges, researchers have developed and investigated various new types of tumor antigens with higher antigenic specificity and broader antigen spectrum, such as tumor-specific peptide antigens, tumor lysates, tumor cell membrane, tumor associated exosomes, etc. At the same time, different nanoparticulate delivery platforms have been developed to increase the immunogenicity of the tumor antigens, for example by increasing their targeting efficiency of antigen-presenting cells and lymph nodes, and by co-delivering antigens with adjuvants. In this review, we summarized different types of the tumor antigens that have been reported, and introduced several nanovaccine strategies for increasing the immunogenicity of tumor antigens. The review of recent progress in these fields may provide reference for the follow-up studies of tumor antigen-based cancer immunotherapy.

Self-adjuvanting photosensitizer nanoparticles for combination photodynamic immunotherapy

Combination cancer immunotherapy that synergizes the advantages of multiple therapeutic agents has shown great potential in tumor treatment. Herein, we report the one-step assembly of therapeutic nanoparticles (NPs) to co-deliver photosensitizers and adjuvants for combination photodynamic therapy (PDT) and immunotherapy. The NPs are obtained via self-assembly of chlorin e6 (Ce6) and imidazoquinoline-based TLR7 agonists (IMDQ), which results in a high loading efficacy of 72.2% and 27.8% for Ce6 and IMDQ, respectively. Upon laser irradiation, the resulting NPs could not only effectively induce photodynamic immunogenic cancer cell death, but also elicit robust antitumor immunity, leading to significant inhibition of both primary and distant tumors in a bilateral tumor model. This study demonstrates the potential of self-assembled NPs in co-delivering multiple therapeutics for potential immunotherapy to enhance the antitumor efficacy.

Design of Polymeric Carriers for Intracellular Peptide Delivery in Oncology Applications

In recent decades, peptides, which can possess high potency, excellent selectivity, and low toxicity, have emerged as promising therapeutics for cancer applications. Combined with an improved understanding of tumor biology and immuno-oncology, peptides have demonstrated robust antitumor efficacy in preclinical tumor models. However, the translation of peptides with intracellular targets into clinical therapies has been severely hindered by limitations in their intrinsic structure, such as low systemic stability, rapid clearance, and poor membrane permeability, that impede intracellular delivery. In this Review, we summarize recent advances in polymer-mediated intracellular delivery of peptides for cancer therapy, including both therapeutic peptides and peptide antigens. We highlight strategies to engineer polymeric materials to increase peptide delivery efficiency, especially cytosolic delivery, which plays a crucial role in potentiating peptide-based therapies. Finally, we discuss future opportunities for peptides in cancer treatment, with an emphasis on the design of polymer nanocarriers for optimized peptide delivery.

Development of PDA Nanoparticles for H9N2 Avian Influenza BPP-V/BP-IV Epitope Peptide Vaccines: Immunogenicity and Delivery Efficiency Improvement

The protection of current influenza vaccines is limited due to the viral antigenic shifts and antigenic drifts. The universal influenza vaccine is a new hotspot in vaccine research that aims to overcome these problems. Polydopamine (PDA), a versatile biomaterial, has the advantages of an excellent biocompatibility, controllable particle size, and distinctive drug loading approach in drug delivery systems. To enhance the immunogenicities and delivery efficiencies of H9N2 avian influenza virus (AIV) epitope peptide vaccines, PDA nanoparticles conjugated with the BPP-V and BP-IV epitope peptides were used to prepare the nano BPP-V and BP-IV epitope peptide vaccines, respectively. The characteristics of the newly developed epitope peptide vaccines were then evaluated, revealing particle sizes ranging from approximately 240 to 290 nm (PDI<0.3), indicating that the synthesized nanoparticles were stable. Simultaneously, the immunoprotective effects of nano BPP-V and BP-IV epitope peptide vaccines were assessed. The nano BPP-V and BP-IV epitope vaccines, especially nano BP-IV epitope vaccine, quickly induced anti-hemagglutinin (HA) antibody production and a sustained immune response, significantly promoted humoral and cellular immune responses, reduced viral lung damage and provided effective protection against AIV viral infection. Together, these results reveal that PDA, as a delivery carrier, can improve the immunogenicities and delivery efficiencies of H9N2 AIV nano epitope vaccines, thereby providing a theoretical basis for the design and development of PDA as a carrier of new universal influenza vaccines.

Immunomodulatory nanomedicine for colorectal cancer treatment: a landscape to be explored?

Colorectal cancer (CRC) is one of the deadliest cancers in the world mainly due to metastasis events. Despite improvements, the available treatment modalities for metastatic cases are limited, being generally associated with poor prognosis. As is well known, the immunosuppressive tumor microenvironment (TME) plays a key role in tumorigenesis, promoting cancer cell immune escape and disease progression. In addition, accumulating evidence indicates that the immunosuppressive microenvironment is a critical barrier for antitumor immunity in CRC, being extremely important to modulate the immune microenvironment to inhibit the tumor-promoting immune response. Therefore, new and effective cancer immunotherapeutic approaches demand a better control over the TME to reverse these immunosuppressive conditions. According to the features of different nanomedicines, nanoparticles can constitute a promising strategy, using different materials with the inherent ability to modulate TME and also with the potential to target immunosuppressive cells, to deliver antigens or immunomodulatory agents to eliminate this tumor. In this review, we summarize the importance of the TME in the progression and treatment response of CRC, exploring the potential of the nanotechnology for the development of immunomodulatory therapeutic strategies.

Phenolic-enabled nanotechnology: versatile particle engineering for biomedicine

Phenolics are ubiquitous in nature and have gained immense research attention because of their unique physiochemical properties and widespread industrial use. In recent decades, their accessibility, versatile reactivity, and relative biocompatibility have catalysed research in phenolic-enabled nanotechnology (PEN) particularly for biomedical applications which have been a major benefactor of this emergence, as largely demonstrated by polydopamine and polyphenols. Therefore, it is imperative to overveiw the fundamental mechanisms and synthetic strategies of PEN for state-of-the-art biomedical applications and provide a timely and comprehensive summary. In this review, we will focus on the principles and strategies involved in PEN and summarize the use of the PEN synthetic toolkit for particle engineering and the bottom-up synthesis of nanohybrid materials. Specifically, we will discuss the attractive forces between phenolics and complementary structural motifs in confined particle systems to synthesize high-quality products with controllable size, shape, composition, as well as surface chemistry and function. Additionally, phenolic's numerous applications in biosensing, bioimaging, and disease treatment will be highlighted. This review aims to provide guidelines for new scientists in the field and serve as an up-to-date compilation of what has been achieved in this area, while offering expert perspectives on PEN's use in translational research.

Engineering a sustained release vaccine with a pathogen-mimicking manner for robust and durable immune responses

Sustained release vaccine carriers can facilitate an increased interaction time between the antigen and immune system to strengthen immune responses, but their promotion on adaptive immune responses, especially cellular immunity, are still unfavorable. Herein, we report a sustained antigen delivery vector, which carries abundant antigens, a nucleic acid adjuvant and pathogen-associated molecular patterns to simulate a natural pathogen to reinforce immune responses. Specifically, murine colorectal cancer cells MC38 lysate and Toll-like receptor 9 agonist CpG are loaded into yeast derived β-glucan particles (GPs). After vaccination, these particles can form a vaccine depot that continuously release the antigen similar to the traditional aluminum hydroxide gel, but recruit more immune cells and induce more cytokine secretion at the injection site. Stronger antibody responses, Th1 and Th17 biased cellular immunity and immune memory are achieved compared with aluminum hydroxide gel. More importantly, treatment with these particles significantly suppress tumor growth in a therapeutic tumor model. This work shed light on the efficacy of combining sustained antigen release with pathogen-mimicking manner in vaccine design.

Phase-Transformation Nanoparticle-Mediated Sonodynamic Therapy: An Effective Modality to Enhance Anti-Tumor Immune Response by Inducing Immunogenic Cell Death in Breast Cancer

Purpose

Immunologically quiescent of breast cancer cells has been recognized as the key impediment for the breast cancer immunotherapy. In this study, we aimed to investigate the role of nanoparticle-mediated sonodynamic therapy (SDT) in promoting anti-tumor immune of breast cancer cells and its potential immune mechanisms.

Materials and Methods

The phase-transformation nanoparticles (LIP-PFH nanoparticles) were in-house prepared and its physiochemical characters were detected. The CCK-8 assay, apoptosis analysis and Balb/c tumor model establishment were used to explore the anti-tumor effect of LIP-PFH nanoparticles triggered by low-intensity focused ultrasound (LIFU) both in vitro and in vivo. Flow cytometry and immunohistochemistry of CD4⁺T, CD8⁺T, CD8⁺PD-1⁺T in blood, spleen and tumor tissue were performed to represent the change of immune response. Detection of immunogenic cell death (ICD) markers was examined to study the potential mechanisms.

Results

LIP-PFH nanoparticles triggered by LIFU could inhibit the proliferation and promote the apoptosis of 4T1 cells both in vitro and in vivo. CD4⁺T and CD8⁺T cell subsets were significantly increased in blood, spleen and tumor tissue, meanwhile CD8⁺PD-1⁺T cells were reduced, indicating enhancement of anti-tumor immune response of breast cancer cells in the nanoparticle-mediated SDT group. Detection of ICD markers (ATP, high-mobility group box B1, and calreticulin) and flow cytometric analysis of dendritic cell (DC) maturity further showed that the nanoparticle-mediated SDT can promote DC maturation to increase the proportion of cytotoxic T cells by inducing ICD of breast cancer cells.

Conclusion

The therapy of nanoparticles-mediated SDT can effectively enhance anti-tumor immune response of breast cancer.

Polymeric Micelles in Cancer Immunotherapy

Cancer immunotherapies have generated some miracles in the clinic by orchestrating our immune system to combat cancer cells. However, the safety and efficacy concerns of the systemic delivery of these immunostimulatory agents has limited their application. Nanomedicine-based delivery strategies (e.g., liposomes, polymeric nanoparticles, silico, etc.) play an essential role in improving cancer immunotherapies, either by enhancing the anti-tumor immune response, or reducing their systemic adverse effects. The versatility of working with biocompatible polymers helps these polymeric nanoparticles stand out as a key carrier to improve bioavailability and achieve specific delivery at the site of action. This review provides a summary of the latest advancements in the use of polymeric micelles for cancer immunotherapy, including their application in delivering immunological checkpoint inhibitors, immunostimulatory molecules, engineered T cells, and cancer vaccines.

CAR-T cells for Colorectal Cancer: Target-selection and strategies for improved activity and safety

Chimeric antigen receptor-T (CAR-T) cell immunotherapy is a novel method that is genetically engineered to recruit T cells against malignant disease. Administration of CAR-T cells has led to progress in hematological malignancies, and it has been proposed for solid tumors like colorectal cancer (CRC) for years. However, this method was not living up to expectations for the intrinsic challenges posed to CAR-T cells by solid tumors, which mainly due to the lacking of tumor-restricted antigens and adverse effects following treatment. New approaches are proposed to overcome the multiple challenges to alleviate the difficult situation of CAR-T cells in CRC, including engineering T cells with immune-activating molecules, regional administration of T cell, bispecific T cell engager, and combinatorial target-antigen recognition. In this review, we sum up the current stage of knowledge about target-selection, adverse events like on/off-tumor toxicity, the preclinical and clinical studies of CAR-T therapy, and the characteristics of strategies applied in CRC.

Recent Advances in a Polydopamine-Mediated Antimicrobial Adhesion System

The drug resistance developed by bacteria during antibiotic treatment has been a call to action for researchers and scientists across the globe, as bacteria and fungi develop ever increasing resistance to current drugs. Innovative antimicrobial/antibacterial materials and coatings to combat such infections have become a priority, as many infections are caused by indwelling implants (e.g., catheters) as well as improving postsurgical function and outcomes. Pathogenic microorganisms that can exist either in planktonic form or as biofilms in water-carrying pipelines are one of the sources responsible for causing water-borne infections. To combat this, researchers have developed nanotextured surfaces with bactericidal properties mirroring the topographical features of some natural antibacterial materials. Protein-based adhesives, secreted by marine mussels, contain a catecholic amino acid, 3,4-dihydroxyphenylalanine (DOPA), which, in the presence of lysine amino acid, empowers with the ability to anchor them to various surfaces in both wet and saline habitats. Inspired by these features, a novel coating material derived from a catechol derivative, dopamine, known as polydopamine (PDA), has been designed and developed with the ability to adhere to almost all kinds of substrates. Looking at the immense potential of PDA, this review article offers an overview of the recent growth in the field of PDA and its derivatives, especially focusing the promising applications as antibacterial nanocoatings and discussing various antimicrobial mechanisms including reactive oxygen species-mediated antimicrobial properties.

Synthesis of mussel-inspired polydopamine-gallium nanoparticles for biomedical applications

Aim: To established a simple, controlled and reproducible method to synthesize gallium (Ga)-coated polydopamine (PDA) nanoparticles (NPs). Materials & methods: PDA NPs were synthesized in alkali medium with posterior Ga shell formation due to ion chelation on the NP surface. Results: The obtained results with energy-dispersive x-ray spectroscopy confirmed the incorporation of Ga on the PDA NP surface. The cytotoxicity of Ga-coated PDA NPs was evaluated in vitro at different concentrations in contact with human adipose-derived stem cells. Further cell analysis also demonstrated the benefit of Ga-coated PDA NPs, which increased the cell proliferation rate compared with noncoated PDA NPs. Conclusion: This study indicated that Ga could work as an appropriate shell for PDA NPs, inducing cell proliferation at the analyzed concentrations.

Polydopamine-Incorporated Nanoformulations for Biomedical Applications

Polydopamine (PDA), a pigment in natural melanin, has attracted considerable attention because of its excellent optical properties, extraordinary adhesion, and good biocompatibility, which make it a promising material for application in energy, environmental, and biomedical fields. In this review, PDA-incorporated nanoformulations are focused for biomedical applications such as drug delivery, bioimaging, and tumor therapy. First, the recent advances in PDA-incorporated nanoformulations for drug delivery are discussed. Further, their application in boimaging, such as fluorescence imaging, photothermal imaging, and photoacoustic imaging, is reviewed. Next, their therapeutic applications, including chemotherapy, photodynamic therapy, photothermal therapy, and synergistic therapy are discussed. Finally, other biomedical applications of PDA-incorporated nanoformulations such as biosensing and clinical diagnosis are briefly presented. Finally, the biomedical applications of PDA-incorporated nanoformulations along with their prospects are summarized.

Mussel-Inspired Polydopamine: The Bridge for Targeting Drug Delivery System and Synergistic Cancer Treatment

Polydopamine (PDA), a mussel-inspired molecule, has been recognized as attractive in cancer therapy due to a number of inherent advantages, such as good biocompatibility, outstanding drug-loading capacity, degradability, superior photothermal conversion efficiency, and low tissue toxicity. Furthermore, due to its strong adhesive property, PDA is able to functionalize various nanomaterials, facilitating the construction of a PDA-based multifunctional platform for targeted or synergistic therapy. Herein, recent PDA research, including targeted drug delivery, single-mode therapy, and diverse synergistic therapies against cancer, are summarized and discussed. For synergistic therapy, advanced developments are highlighted, such as photothermal/radiotherapy, chemo-/photothermal/gene therapy, photothermal/immune therapy, and photothermal/photodynamic/immune therapy. Finally, the challenges and promise of PDA for biomedical applications in the future are discussed.

The Neuropeptide System and Colorectal Cancer Liver Metastases: Mechanisms and Management

Colorectal cancer (CRC), classified as the third most prevalent cancer worldwide, remains to be a clinical and research challenge. It is estimated that ~50% of CRC patients die from distant metastases, with treatment of this complication still posing significant difficulties. While liver metastasis (LM) cascade is known in the literature, its mechanisms are still unclear and remain studied in different research models. A connection is suggested between nervous system dysfunctions and a range of Neurotransmitters (Nts) (including Neuropeptides, NPs), Neurotrophins (Ntt) and their receptors (Rs) in CRC liver metastasis development. Studies on the role of NP/NP-Rs in the progression and metastasis of CRC, show the complexity of brain–tumor interactions, caused by their different forms of release to the extracellular environment (endocrine, autocrine, paracrine and neurocrine). Many stages of LM are connected to the activity of pro-inflammatory, e.g., Corticotropin-releasing Hormone Receptor 1 (CRHR1), Neuropeptide Y (NPY) and Neurotensin (NT), anti-inflammatory, e.g., Calcitonin Gene-related Peptide (CGRP), CRHR2 and Vasoactive Intestinal Polypeptide (VIP) or dual role neuropeptides, e.g., Substance P (SP). The regulation of the local immunological profile (e.g., CRH/CRHRs), dysfunctions of enteroprotective role of NPs on epithelial cells (e.g., NT/NT-R), as well as structural-functional changes in enteric nervous system innervation of the tumor are also important. More research is needed to understand the exact mechanisms of communication between the neurons and tumor cells. The knowledge on the mechanisms regulating tumor growth and different stages of metastasis, as well as effects of the action of a numerous group of Nts/NPs/Ntt as growth factors, have implications for future therapeutic strategies. To obtain the best treatment outcomes, it is important to use signaling pathways common for many NPs, as well to develop a range of broad-spectrum antagonists. This review aims to summarize the current knowledge on the importance of neuroactive molecules in the promotion of the invasion-metastasis cascade in CRC, as well as the improvements of clinical management of CRC liver metastasis.

Nanoparticles modified by polydopamine: Working as "drug" carriers

Inspired by the mechanism of mussel adhesion, polydopamine (PDA), a versatile polymer for surface modification has been discovered. Owing to its unique properties like extraordinary adhesiveness, excellent biocompatibility, mild synthesis requirements, as well as distinctive drug loading approach, strong photothermal conversion capacity and reactive oxygen species (ROS) scavenging facility, various PDA-modified nanoparticles have been desired as drug carriers. These nanoparticles with diverse nanostructures are exploited in multifunctions, consisting of targeting, imaging, chemical treatment (CT), photodynamic therapy (PDT), photothermal therapy (PTT), tissue regeneration ability, therefore have attracted great attentions in plenty biomedical applications. Herein, recent progress of PDA-modified nanoparticle drug carriers in cancer therapy, antibiosis, prevention of inflammation, theranostics, vaccine delivery and adjuvant, tissue repair and implant materials are reviewed, including preparation of PDA-modified nanoparticle drug carriers with various nanostructures and their drug loading strategies, basic roles of PDA surface modification, etc. The advantages of PDA modification in overcoming the existing limitations of cancer therapy, antibiosis, tissue repair and the developing trends in the future of PDA-modified nanoparticle drug carriers are also discussed.

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Multifunctional PDA-modified drug systems are introduced in terms of classification, synthesis and drug loading strategies.

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Basic roles of PDA surface modification in the drug systems are discussed.

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Biomedical applications and unique advantages of the PDA-modified nanoparticle working as drug carriers are illustrated.

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Challenges and perspectives for future development are proposed.

Recent advances in melanin-like nanomaterials in biomedical applications: a mini review

BACKGROUND

Melanins are a group of biopigments in microorganisms that generate a wide range of colorants. Due to their multifunctionality, including ultraviolet protection, radical scavenging, and photothermal conversion, in addition to their intrinsic biocompatibility, natural melanins and synthetic melanin-like nanomaterials have been suggested as novel nano-bio platforms in biomedical applications.

MAIN BODY

Recent approaches in the synthesis of melanin-like nanomaterials and their biomedical applications have briefly been reviewed. Melanin-like nanomaterials have been suggested as endogenous chromophores for photoacoustic imaging and radical scavengers for the treatment of inflammatory diseases. The photothermal conversion ability of these materials under near-infrared irradiation allows hyperthermia-mediated cancer treatments, and their intrinsic fluorescence can be an indicator in biosensing applications. Furthermore, catechol-rich melanin and melanin-like nanomaterials possess a versatile affinity for various functional organic and inorganic additives, allowing the design of multifunctional hybrid nanomaterials that expand their range of applications in bioimaging, therapy, theranostics, and biosensing.

CONCLUSION

Melanin-like natural and synthetic nanomaterials have emerged; however, the under-elucidated chemical structures of these materials are still a major obstacle to the construction of novel nanomaterials through bottom-up approaches and tuning the material properties at the molecular level. Further advancements in melanin-based medical applications can be achieved with the incorporation of next-generation chemical and molecular analytical tools.

Nanovectors Design for Theranostic Applications in Colorectal Cancer

Colorectal cancer (CRC) is a diffused disease with limited therapeutic options, none of which are often curative. Based on the molecular markers and targets expressed by the affected tissues, numerous novel approaches have been developed to study and treat this disease. In particular, the field of nanotechnology offers an astonishingly wide array of innovative nanovectors with high versatility and adaptability for both diagnosis and therapy (the so called “theranostic platforms”). However, such complexity can make the selection of a specific nanocarrier model to study a perplexing endeavour for the biomedical scientist or clinician not familiar with this field of inquiry. This review offers a comprehensive overview of this wide body of knowledge, in order to outline the essential requirements for the clinical viability evaluation of a nanovector model in CRC. In particular, the differences among the foremost designs, their specific advantages, and technological caveats will be treated, never forgetting the ultimate endpoint for these systems development: the clinical practice.