Nanomaterials and their composite scaffolds for photothermal therapy and tissue engineering applications

Smart composite scaffold to synchronize magnetic hyperthermia and chemotherapy for efficient breast cancer therapy

Combination of different therapies is an attractive approach for cancer therapy. However, it is a challenge to synchronize different therapies for maximization of therapeutic effects. In this work, a smart composite scaffold that could synchronize magnetic hyperthermia and chemotherapy was prepared by hybridization of magnetic Fe3O4 nanoparticles and doxorubicin (Dox)-loaded thermosensitive liposomes with biodegradable polymers. Irradiation of alternating magnetic field (AMF) could not only increase the scaffold temperature for magnetic hyperthermia but also trigger the release of Dox for chemotherapy. The two functions of magnetic hyperthermia and chemotherapy were synchronized by switching AMF on and off. The synergistic anticancer effects of the composite scaffold were confirmed by in vitro cell culture and in vivo animal experiments. The composite scaffold could efficiently eliminate breast cancer cells under AMF irradiation. Moreover, the scaffold could support proliferation and adipogenic differentiation of mesenchymal stem cells for adipose tissue reconstruction after anticancer treatment. In vivo regeneration experiments showed that the composite scaffolds could effectively maintain their structural integrity and facilitate the infiltration and proliferation of normal cells within the scaffolds. The composite scaffold possesses multi-functions and is attractive as a novel platform for efficient breast cancer therapy.

Biofilm Inhibition on Medical Devices and Implants Using Carbon Dots: An Updated Review

Biofilms are an intricate community of microbes that colonize solid surfaces, communicating via a quorum-sensing mechanism. These microbial aggregates secrete exopolysaccharides facilitating adhesion and conferring resistance to drugs and antimicrobial agents. The escalating global concern over biofilm-related infections on medical devices underscores the severe threat to human health. Carbon dots (CDs) have emerged as a promising substrate to combat microbes and disrupt biofilm matrices. Their numerous advantages such as facile surface functionalization and specific antimicrobial properties, position them as innovative anti-biofilm agents. Due to their minuscule size, CDs can penetrate microbial cells, inhibiting growth via cytoplasmic leakage, reactive oxygen species (ROS) generation, and genetic material fragmentation. Research has demonstrated the efficacy of CDs in inhibiting biofilms formed by key pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Consequently, the development of CD-based coatings and hydrogels holds promise for eradicating biofilm formation, thereby enhancing treatment efficacy, reducing clinical expenses, and minimizing the need for implant revision surgeries. This review provides insights into the mechanisms of biofilm formation on implants, surveys major biofilm-forming pathogens and associated infections, and specifically highlights the anti-biofilm properties of CDs emphasizing their potential as coatings on medical implants.

Black phosphorus, an advanced versatile nanoparticles of antitumor, antibacterial and bone regeneration for OS therapy

Osteosarcoma (OS) is the most common primary malignant bone tumor. In the clinic, usual strategies for OS treatment include surgery, chemotherapy, and radiation. However, all of these therapies have complications that cannot be ignored. Therefore, the search for better OS treatments is urgent. Black phosphorus (BP), a rising star of 2D inorganic nanoparticles, has shown excellent results in OS therapy due to its outstanding photothermal, photodynamic, biodegradable and biocompatible properties. This review aims to present current advances in the use of BP nanoparticles in OS therapy, including the synthesis of BP nanoparticles, properties of BP nanoparticles, types of BP nanoparticles, and modification strategies for BP nanoparticles. In addition, we have discussed comprehensively the application of BP in OS therapy, including single, dual, and multimodal synergistic OS therapies, as well as studies about bone regeneration and antibacterial properties. Finally, we have summarized the conclusions, limitations and perspectives of BP nanoparticles for OS therapy.

A Ti3C2 MXene-integrated near-infrared-responsive multifunctional porous scaffold for infected bone defect repair

Infected bone defect repair has long been a major challenge in orthopedic surgery. Apart from bacterial contamination, excessive generation of reactive oxygen species (ROS), and lack of osteogenesis ability also threaten the defect repair process. However, few strategies have been proposed to address these issues simultaneously. Herein, we designed and fabricated a near-infrared (NIR)-responsive, hierarchically porous scaffold to address these limitations in a synergetic manner. In this design, polymethyl methacrylate (PMMA) and polyethyleneimine (PEI) were used to fabricate the porous PMMA/PEI scaffolds via the anti-solvent vapor-induced phase separation (VIPS) process. Then, Ti3C2 MXenes were anchored on the scaffolds through the dopamine-assisted co-deposition process to obtain the PMMA/PEI/polydopamine (PDA)/MXene scaffolds. Under NIR laser irradiation, the scaffolds were able to kill bacteria through the direct contact-killing and synergetic photothermal effect of Ti3C2 MXenes and PDA. Moreover, MXenes and PDA also endowed the scaffolds with excellent ROS-scavenging capacity and satisfying osteogenesis ability. Our experimental results also confirmed that the PMMA/PEI/PDA/MXene scaffolds significantly promoted new bone formation in an infected mandibular defect model. We believe that our study provides new insights into the treatment of infected bone defects.

3D Printing Drug-Free Scaffold with Triple-Effect Combination Induced by Copper-Doped Layered Double Hydroxides for the Treatment of Bone Defects

Tissue-engineered poly(l-lactide) (PLLA) scaffolds have been widely used to treat bone defects; however, poor biological activities have always been key challenges for its further application. To address this issue, introducing bioactive drugs or factors is the most commonly used method, but there are often many problems such as high cost, uncontrollable and monotonous drug activity, and poor bioavailability. Here, a drug-free 3D printing PLLA scaffold with a triple-effect combination induced by surface-modified copper-doped layered double hydroxides (Cu-LDHs) is proposed. In the early stage of scaffold implantation, Cu-LDHs exert a photothermal therapy (PTT) effect to generate high temperature to effectively prevent bacterial infection. In the later stage, Cu-LDHs can further have a mild hyperthermia (MHT) effect to stimulate angiogenesis and osteogenic differentiation, demonstrating excellent vascularization and osteogenic activity. More importantly, with the degradation of Cu-LDHs, the released Cu2+ and Mg2+ provide an ion microenvironment effect and further synergize with the MHT effect to stimulate angiogenesis and osteogenic differentiation, thus more effectively promoting the healing of bone tissue. This triple-effect combined scaffold exhibits outstanding antibacterial, osteogenic, and angiogenic activities, as well as the advantages of low cost, convenient procedure, and long-term efficacy, and is expected to provide a promising strategy for clinical repair of bone defects.

Algae: A Robust Living Material Against Cancer

Cancer is the second leading cause of death worldwide. Its incidence has been increasing in recent years, and it is becoming a major threat to human health. Conventional cancer treatment strategies, including surgery, chemotherapy, and radiotherapy, have faced problems such as drug resistance, toxic side effects and unsatisfactory therapeutic efficacy. Therefore, better development and utilization of biomaterials can improve the specificity and efficacy of tumor therapy. Algae, as a novel living material, possesses good biocompatibility. Although some reviews have elucidated several algae-based biomaterials for cancer treatment, the majority of the literature has focused on a limited number of algae. As a result, there is currently a lack of comprehensive reviews on the subject of anticancer algae. This review aims to address this gap by conducting a thorough examination of algal species that show potential for anticancer activity. Furthermore, our review will also elucidate the engineering strategies of algae and discuss the challenges and prospects associated with their implementation.

Recent Advances in Metal-Organic Framework (MOF) Asymmetric Membranes/Composites for Biomedical Applications

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials composed of metal and organic material. MOFs have fascinating properties, such as fine tunability, large specific surface area, and high porosity. MOFs are widely used for environmental protection, biosensors, regenerative medicine, medical engineering, cell therapy, catalysts, and drug delivery. Recent studies have reported various significant properties of MOFs for biomedical applications, such as drug detection and delivery. In contrast, MOFs have limitations such as low stability and low specificity in binding to the target. MOF-based membranes improve the stability and specificity of conventional MOFs by increasing the surface area and developing the possibility of MOF-ligand binding, while conjugated membranes dramatically increase the area of active functional groups. This special property makes them attractive for drug and biosensor fabrication, as both the spreading and solubility components of the porosity can be changed. Asymmetric membranes are a structure with high potential in the biomedical field, due to the different characteristics on its two surfaces, the possibility of adjusting various properties such as the size of porosity, transfer rate and selectivity, and surface properties such as hydrophilicity and hydrophobicity. MOF assisted asymmetric membranes can provide a platform with different properties and characteristics in the biomedical field. The latest version of MOF materials/membranes has several potential applications, especially in medical engineering, cell therapy, drug delivery, and regenerative medicine, which will be discussed in this review, along with their advantages, disadvantages, and challenges.

Composite Scaffolds of Gelatin and Fe3 O4 Nanoparticles for Magnetic Hyperthermia-Based Breast Cancer Treatment and Adipose Tissue Regeneration

Postsurgical treatment of breast cancer remains a challenge with regard to killing residual cancer cells and regenerating breast defects. To prepare composite scaffolds for postoperative use, gelatin is chemically modified with folic acid (FA) and used for hybridization with citrate-modified Fe₃ O₄ nanoparticles (Fe₃ O₄ -citrate NPs) to fabricate Fe₃ O₄ /gelatin composite scaffolds which pore structures are controlled by free ice microparticles. The composite scaffolds have large spherical pores that are interconnected to facilitate cell entry and exit. The FA-functionalized composite scaffolds have the ability to capture breast cancer cells. The Fe₃ O₄ /gelatin composite scaffolds possess a high capacity for magnetic-thermal conversion to ablate breast cancer cells during alternating magnetic field (AMF) irradiation. In addition, the composite scaffolds facilitate the growth and adipogenesis of mesenchymal stem cells. The composite scaffolds have multiple functions for eradication of residual cancer cells under AMF irradiation and for regeneration of resected adipose tissue when AMF is off.

Silica-Capped and Gold-Decorated Silica Nanoparticles for Enhancing Effect of Gold Nanoparticle-Based Photothermal Therapy

BACKGROUND

Various methods based on gold nanoparticles (AuNPs) have been applied to enhance the photothermal effect. Among these methods, combining gold nanoparticles and stem cells has been suggested as a new technique for elevating the efficiency of photothermal therapy (PT) in terms of enhancing tumor targeting effect. However, to elicit the efficiency of PT using gold nanoparticles and stem cells, delivering large amounts of AuNPs into stem cells without loss should be considered.

METHODS

AuNPs, AuNPs-decorated silica nanoparticles, and silica-capped and AuNPs-decorated silica nanoparticles (SGSs) were synthesized and used to treat human mesenchymal stem cells (hMSCs). After evaluating physical properties of each nanoparticle, the concentration of each nanoparticle was estimated based on its cytotoxicity to hMSCs. The amount of AuNPs loss from each nanoparticle by exogenous physical stress was evaluated after exposing particles to a gentle shaking. After these experiments, in vitro and in vivo photothermal effects were then evaluated.

RESULTS

SGS showed no cytotoxicity when it was used to treat hMSCs at concentration up to 20 μg/mL. After intravenous injection to tumor-bearing mice, SGS-laden hMSCs group showed significantly higher heat generation than other groups following laser irradiation. Furthermore, in vivo photothermal effect in the hMSC-SGS group was significantly enhanced than those in other groups in terms of tumor volume decrement and histological outcome.

CONCLUSION

Our results suggest that additional silica layer in SGSs could protect AuNPs from physical stress induced AuNPs loss. The strategy applied in SGS may offer a prospective method to improve PT.

Manganese-based Prussian blue nanoparticles inhibit tumor proliferation and migration via the MAPK pathway in pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest gastrointestinal malignancies. Advances in molecular biology and surgery have significantly improved survival rates for other tumors in recent decades, but clinical outcomes for PC remained relatively unchanged. Chemodynamic therapy (CDT) and Photothermal therapy (PTT) represent an efficient and relatively safe cancer treatment modality. Here, we synthesized Mn-doped Prussian blue nanoparticles (MnPB NPs) through a simple and mild method, which have a high loading capacity for drugs and excellent CDT/PTT effect. Cell line experiments in vitro and animal experiments in vivo proved the safety of MnPB NPs. We stimulated the PC cells with MnPB NPs and performed transwell migration assays. The migration of PC cells was reduced company with the decrease of two classical proteins: matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Moreover, MnPB NPs induced ferroptosis, which mediated the MAPK pathway and achieved tumor elimination in nude mice. This effective and safe strategy controlled by irradiation represents a promising strategy for pancreatic cancer.

NIR Photothermal-Responsive Shape Memory Polyurethane with Protein-Inspired Aggregated Chymotrypsin-Sensitive Degradable Domains

Biodegradable shape memory polymers are promising biomaterials for stents used in minimally invasive surgical procedures such as intestinal stents. Herein, a series of biodegradable shape memory polyurethanes (SMPUs) containing a novel phenylalanine-derived chain extender PHP were synthesized. Inspired by the fact that the function of biomacromolecules such as proteins is rich and varied because of the multiple combinations of the amino acid in highly evolved biosystems, we found that the sequence distribution of PHP in SMPU would also have a great influence on the phase structure and degradation behavior, especially the difference of surface morphology caused by degradation. Considering that the transition temperature (T_trans ) of SMPU we obtained is higher than physiological temperature, oxidized carbon black (OCB) with the ability of photothermal conversion was introduced into SMPU, which can not only endow SMPU with near-infrared response shape recovery characteristics, but also enhance phase separation degree and mechanical properties of them. SMPU/OCB composites show excellent shape memory effect and rapid photothermal response, and they can be degraded by chymotrypsin with an adjustable degradation rate. These SMPU/OCB composites show broad potential for application as intestinal stents. This article is protected by copyright. All rights reserved.

Recent advances in nanoparticle-based photothermal therapy for breast cancer

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

Preparation of composite scaffolds composed of gelatin and Au nanostar-deposited black phosphorus nanosheets for the photothermal ablation of cancer cells and adipogenic differentiation of stem cells

Photothermal nanoparticles are important in photothermal therapy. Combining different nanoparticles can achieve a high photothermal capacity. In this study, composite nanoparticles composed of black phosphorus nanosheets (BPNSs) and gold nanostars (BP-AuNSs) were synthesized by using BPNSs as the reductant. AuNSs were deposited on the BPNSs. The BP-AuNSs were further hybridized with porous gelatin scaffolds to prepare gelatin-BP-AuNS composite scaffolds. The gelatin-BP-AuNS composite scaffolds promoted cell migration and distribution. The synergistic effects of the BPNSs and AuNSs endowed the gelatin-BP-AuNS composite scaffolds with excellent photothermal properties. The gelatin-BP-AuNS composite scaffolds eliminated cancer cells after near infrared laser exposure and supported the adipogenic differentiation of human mesenchymal stem cells. Thus, this gelatin-BP-AuNS composite scaffold holds promise for breast cancer therapy.

Doxorubicin-encapsulated thermosensitive liposome-functionalized photothermal composite scaffolds for synergistic photothermal therapy and chemotherapy

Synergistic therapy, especially the combination of photothermal therapy and chemotherapy, has been proposed as an effective therapeutic approach for breast cancer treatment. In this study, a smart platform for synergistic photothermal therapy and chemotherapy was developed by hybridizing doxorubicin-encapsulated thermosensitive liposomes and gold nanorods into porous scaffolds of gelatin and polyglutamic acid (Dox-lipo/AuNR/Gel/PGA). The Dox-lipo/AuNR/Gel/PGA composite scaffolds had good photothermal conversion and temperature-dependent doxorubicin release properties. Under near-infrared laser irradiation, the composite scaffolds increased the local temperature to not only kill the breast cancer cells in the scaffolds but also accelerate the release of doxorubicin to eliminate the breast cancer cells surrounding the scaffolds. In vitro cell culture and in vivo mouse experiments demonstrated that the synergistic effects of photothermal ablation combined with doxorubicin-induced inhibition of the breast cancer cells in and surrounding the composite scaffolds under near-infrared laser irradiation. Moreover, after drug release was complete, the composite scaffolds fostered human bone marrow-derived mesenchymal stem cell proliferation. These results suggested that the composite scaffolds provided synergistic photothermal therapy and chemotherapy for breast cancer cell elimination at the early stage and promoted stem cell activities at the late stage. Therefore, this composite scaffold holds great potential as a synergistic therapy platform for breast cancer treatment.

H2O2 generation enhancement by ultrasonic nebulisation with a zinc layer for spray disinfection

With the outbreak of COVID-19, microbial pollution has gained increasing attention as a threat to human health. Consequently, many research efforts are being devoted to the development of efficient disinfection methods. In this context, hydrogen peroxide (H₂O₂) stands out as a green and broad-spectrum disinfectant, which can be produced and sprayed in the air directly by cavitation in ultrasonic nebulisation. However, the yield of H₂O₂ obtained by ultrasonic nebulisation is too low to satisfy the requirements for disinfection by spraying and needs to be improved to achieve efficient disinfection of the air and objects. Herein, we report the introduction of a zinc layer into an ultrasonic nebuliser to improve the production of H₂O₂ and generate additional Zn²⁺ by self-corrosion, achieving good disinfecting performance. Specifically, a zinc layer was assembled on the oscillator plate of a commercial ultrasonic nebuliser, resulting in a 21-fold increase in the yield of H₂O₂ and the production of 4.75 μg/mL Zn²⁺ in the spraying droplets. When the generated water mist was used to treat a bottle polluted with Escherichia coli for 30 min, the sterilisation rate reached 93.53%. This ultrasonic nebulisation using a functional zinc layer successfully enhanced the production of H₂O₂ while generating Zn²⁺, providing a platform for the development of new methodologies of spray disinfection.

Photo-induced processes of iron oxide nanoparticles to enhance laser therapy

Nanoparticles are used as drug carriers to increase the selectivity and effectiveness of therapy, as well as for combined therapy that utilizes different effects. Iron oxide nanoparticles are promising in this aspect. Due to magnetic properties, they can be used as a contrast agent for magnetic resonance imaging. Also, iron oxide nanoparticles could be coated with a photosensitizer for photodynamic therapy and their laser or magnetic heating can be used for phototherapy. Local enhancement of the electromagnetic field near iron oxide nanoparticles can increase the fluorescence intensity of photosensitizers and the efficiency of singlet oxygen generation. This paper presents the results of a study of iron oxide nanoparticles focused on the photophysical aspects of the formation of “hot spots” under laser irradiation. The photoinduced effects of iron oxide nanoparticles observed in in vitro experiments lead to the rupture of lysosomes. Theoretical modeling showed that the heating of iron oxide nanoparticles with a radius of 35 nm under the action of laser radiation is about 89°C and 19°C for wavelengths of 458 and 561 nm, respectively. Local field enhancement occurs in pairs of nanoparticles of various sizes and strongly depends on the distance between them. The maximum gain is achieved at small distances between nanoparticles. For a dimer of nanoparticles with radii of 10 and 35 nm at a distance of 1 nm, an enhancement factor of two orders of magnitude was obtained. The investigated phenomenon of «hot spots» is in demand for precision therapy, because the photo-induced processes occur at small distances between nanoparticles, in areas of their high accumulation.

Confined in-situ polymerization in nanoscale porphyrinic metal-organic framework for fluorescence imaging-guided synergistic phototherapy

Engineering a versatile nanoplatform integrating imaging and therapeutic functions for efficient cancer treatment remains grand challenge. Herein, a type of metal-organic framework (MOF)-based hybrid material for fluorescence imaging-guided synergistic phototherapy...

Regulation of stem cell fate and function by using bioactive materials with nanoarchitectonics for regenerative medicine

Nanoarchitectonics has emerged as a post-nanotechnology concept. As one of the applications of nanoarchitectonics, this review paper discusses the control of stem cell fate and function as an important issue. For hybrid nanoarchitectonics involving living cells, it is crucial to understand how biomaterials and their nanoarchitected structures regulate behaviours and fates of stem cells. In this review, biomaterials for the regulation of stem cell fate are firstly discussed. Besides multipotent differentiation, immunomodulation is an important biological function of mesenchymal stem cells (MSCs). MSCs can modulate immune cells to treat multiple immune- and inflammation-mediated diseases. The following sections summarize the recent advances of the regulation of the immunomodulatory functions of MSCs by biophysical signals. In the third part, we discussed how biomaterials direct the self-organization of pluripotent stem cells for organoid. Bioactive materials are constructed which mimic the biophysical cues of in vivo microenvironment such as elasticity, viscoelasticity, biodegradation, fluidity, topography, cell geometry, and etc. Stem cells interpret these biophysical cues by different cytoskeletal forces. The different cytoskeletal forces lead to substantial transcription and protein expression, which affect stem cell fate and function. Regulations of stem cells could not be utilized only for tissue repair and regenerative medicine but also potentially for production of advanced materials systems. Materials nanoarchitectonics with integration of stem cells and related biological substances would have high impacts in science and technology of advanced materials.

Bioactivity of PEGylated Graphene Oxide Nanoparticles Combined with Near-Infrared Laser Irradiation Studied in Colorectal Carcinoma Cells

Central focus in modern anticancer nanosystems is given to certain types of nanomaterials such as graphene oxide (GO). Its functionalization with polyethylene glycol (PEG) demonstrates high delivery efficiency and controllable release of proteins, bioimaging agents, chemotherapeutics and anticancer drugs. GO-PEG has a good biological safety profile, exhibits high NIR absorbance and capacity in photothermal treatment. To investigate the bioactivity of PEGylated GO NPs in combination with NIR irradiation on colorectal cancer cells we conducted experiments that aim to reveal the molecular mechanisms of action of this nanocarrier, combined with near-infrared light (NIR) on the high invasive Colon26 and the low invasive HT29 colon cancer cell lines. During reaching cancer cells the phototoxicity of GO-PEG is modulated by NIR laser irradiation. We observed that PEGylation of GO nanoparticles has well-pronounced biocompatibility toward colorectal carcinoma cells, besides their different malignant potential and treatment times. This biocompatibility is potentiated when GO-PEG treatment is combined with NIR irradiation, especially for cells cultured and treated for 24 h. The tested bioactivity of GO-PEG in combination with NIR irradiation induced little to no damages in DNA and did not influence the mitochondrial activity. Our findings demonstrate the potential of GO-PEG-based photoactivity as a nanosystem for colorectal cancer treatment.

Carbon Dots as an Emergent Class of Antimicrobial Agents

Antimicrobial resistance is a recognized global challenge. Tools for bacterial detection can combat antimicrobial resistance by facilitating evidence-based antibiotic prescribing, thus avoiding their overprescription, which contributes to the spread of resistance. Unfortunately, traditional culture-based identification methods take at least a day, while emerging alternatives are limited by high cost and a requirement for skilled operators. Moreover, photodynamic inactivation of bacteria promoted by photosensitisers could be considered as one of the most promising strategies in the fight against multidrug resistance pathogens. In this context, carbon dots (CDs) have been identified as a promising class of photosensitiser nanomaterials for the specific detection and inactivation of different bacterial species. CDs possess exceptional and tuneable chemical and photoelectric properties that make them excellent candidates for antibacterial theranostic applications, such as great chemical stability, high water solubility, low toxicity and excellent biocompatibility. In this review, we will summarize the most recent advances on the use of CDs as antimicrobial agents, including the most commonly used methodologies for CD and CD/composites syntheses and their antibacterial properties in both in vitro and in vivo models developed in the last 3 years.

A review of regulated self-organizing approaches for tissue regeneration

Tissue and organ regeneration is the dynamic process by which a population of cells rearranges into a specific form with specific functions. Traditional tissue regeneration utilizes tissue grafting, cell implantation, and structured scaffolds to achieve clinical efficacy. However, tissue grafting methods face a shortage of donor tissue, while cell implantation may involve leakage of the implanted cells without a supportive 3D matrix. Cell migration, proliferation, and differentiation in structured scaffolds may disorganize and frustrate the artificially pre-designed structures, and sometimes involve immunogenic reactions. To overcome this limitation, the self-organizing properties and innate regenerative capability of tissue/organism formation in the absence of guidance by structured scaffolds has been investigated. This review emphasizes the growing subfield of the regulated self-organizing approach for neotissue formation and describes advances in the subfield using diverse, cutting-edge, inter-disciplinarity technologies. We cohesively summarize the directed self-organization of cells in the micro-engineered cell-ECM system and 3D/4D cell printing. Mathematical modeling of cellular self-organization is also discussed for providing rational guidance to intractable problems in tissue regeneration. It is envisioned that future self-organization approaches integrating biomathematics, micro-nano engineering, and gene circuits developed from synthetic biology will continue to work in concert with self-organizing morphogenesis to enhance rational control during self-organizing in tissue and organ regeneration.