Near-Infrared Light-Responsive Size-Selective Lateral Flow Chip for Single-Cell Manipulation of Circulating Tumor Cells.

Accurately obtaining information on the heterogeneity of CTCs at the single-cell level is a very challenging task that may facilitate cancer pathogenesis research and personalized therapy. However, commonly used multicellular population capture and release assays tend to lose effective information on heterogeneity and cannot accurately assess molecular-level studies and drug resistance assessment of CTCs in different stages of tumor metastasis. Herein, we designed a near-infrared (NIR) light-responsive microfluidic chip for biocompatible single-cell manipulation and study the heterogeneity of CTCs by a combination of the lateral flow microarray (LFM) chip and photothermal response system. First, immunomagnetic labeling and a gradient magnetic field were combined to distribute CTCs in different regions of the chip according to the content of surface markers. Subsequently, the LFM chip achieves high single-cell capture efficiency and purity (even as low as 5 CTCs per milliliter of blood) under the influence of lateral fluid and magnetic fields. Due to the rapid dissolution of the gelatin capture structure at 37 °C and the photothermal properties of gold nanorods, the captured single CTC cell can be recovered in large quantities at physiological temperature or released individually at a specific point by NIR. The multifunctional NIR-responsive LFM chip demonstrates excellent performance in capture and site release of CTCs with high viability, which provides a robust and versatile means for CTCs heterogeneity study at the single-cell level.

Surfactant like peptides for targeted gene delivery to cancer cells.

Surfactant like peptides (SLPs) are a class of amphiphilic peptides widely used for drug delivery and tissue engineering. However, there are very few reports on their application for gene delivery. The current study was aimed at development of two new SLPs, named (IA)4K and (IG)4K, for selective delivery of antisense oligodeoxynucleotides (ODNs) and small interfering RNA (siRNA) to cancer cells. The peptides were synthesized by Fmoc solid phase synthesis. Their complexation with nucleic acids was studied by gel electrophoresis and DLS. The transfection efficiency of the peptides was assessed in HCT 116 colorectal cancer cells and human dermal fibroblasts (HDFs) using high content microscopy. The cytotoxicity of the peptides was assessed by standard MTT test. The interaction of the peptides with model membranes was studied using CD spectroscopy. Both SLPs delivered siRNA and ODNs to HCT 116 colorectal cancer cells with high transfection efficiency which was comparable to the commercial lipid-based transfection reagents, but with higher selectivity for HCT 116 compared to HDFs. Moreover, both peptides exhibited very low cytotoxicity even at high concentrations and long exposure time. The current study provides more insights into the structural features of SLPs required for nucleic acid complexation and delivery and can therefore serve as a guide for the rational design of new SLPs for selective gene delivery to cancer cells to minimize the adverse effects in healthy tissues.

Silk Fibroin as a Functional Biomaterial for Tissue Engineering.

Tissue engineering (TE) is the approach to combine cells with scaffold materials and appropriate growth factors to regenerate or replace damaged or degenerated tissue or organs. The scaffold material as a template for tissue formation plays the most important role in TE. Among scaffold materials, silk fibroin (SF), a natural protein with outstanding mechanical properties, biodegradability, biocompatibility, and bioresorbability has attracted significant attention for TE applications. SF is commonly dissolved into an aqueous solution and can be easily reconstructed into different material formats, including films, mats, hydrogels, and sponges via various fabrication techniques. These include spin coating, electrospinning, freeze drying, physical, and chemical crosslinking techniques. Furthermore, to facilitate fabrication of more complex SF-based scaffolds with high precision techniques including micro-patterning and bio-printing have recently been explored. This review introduces the physicochemical and mechanical properties of SF and looks into a range of SF-based scaffolds that have been recently developed. The typical TE applications of SF-based scaffolds including bone, cartilage, ligament, tendon, skin, wound healing, and tympanic membrane, will be highlighted and discussed, followed by future prospects and challenges needing to be addressed.

Recent Advances in Microfluidics for the Preparation of Drug and Gene Delivery Systems.

Drug delivery systems (DDSs) have great potential for improving the treatment of several diseases, especially microbial infections and cancers. However, the formulation procedures of DDSs remain challenging, especially at the nanoscale. Reducing batch-to-batch variation and enhancing production rate are some of the essential requirements for accelerating the translation of DDSs from a small scale to an industrial level. Microfluidic technologies have emerged as an alternative to the conventional bench methods to address these issues. By providing precise control over the fluid flows and rapid mixing, microfluidic systems can be used to fabricate and engineer different types of DDSs with specific properties for efficient delivery of a wide range of drugs and genetic materials. This review discusses the principles of controlled rapid mixing that have been employed in different microfluidic strategies for producing DDSs. Moreover, the impact of the microfluidic device design and parameters on the type and properties of DDS formulations was assessed, and recent applications in drug and gene delivery were also considered.

Interfacial Assembly Inspired by Marine Mussels and Antifouling Effects of Polypeptoids: A Neutron Reflection Study.

Polypeptoid-coated surfaces and many surface-grafted hydrophilic polymer brushes have been proven efficient in antifouling-the prevention of nonspecific biomolecular adsorption and cell attachment. Protein adsorption, in particular, is known to mediate subsequent cell-surface interactions. However, the detailed antifouling mechanism of polypeptoid and other polymer brush coatings at the molecular level is not well understood. Moreover, most adsorption studies focus only on measuring a single adsorbed mass value, and few techniques are capable of characterizing the hydrated in situ layer structure of either the antifouling coating or adsorbed proteins. In this study, interfacial assembly of polypeptoid brushes with different chain lengths has been investigated in situ using neutron reflection (NR). Consistent with past simulation results, NR revealed a common two-step structure for grafted polypeptoids consisting of a dense inner region that included a mussel adhesive-inspired oligopeptide for grafting polypeptoid chains and a highly hydrated upper region with very low polymer density (molecular brush). Protein adsorption was studied with human serum albumin (HSA) and fibrinogen (FIB), two common serum proteins of different sizes but similar isoelectric points (IEPs). In contrast to controls, we observed higher resistance by grafted polypeptoid against adsorption of the larger FIB, especially for longer chain lengths. Changing the pH to close to the IEPs of the proteins, which generally promotes adsorption, also did not significantly affect the antifouling effect against FIB, which was corroborated by atomic force microscopy imaging. Moreover, NR enabled characterization of the in situ hydrated layer structures of the polypeptoids together with proteins adsorbed under selected conditions. While adsorption on bare SiO2 controls resulted in surface-induced protein denaturation, this was not observed on polypeptoids. Our current results therefore highlight the detailed in situ view that NR may provide for characterizing protein adsorption on polymer brushes as well as the excellent antifouling behavior of polypeptoids.

Reactive Inkjet Printing of Functional Silk Stirrers for Enhanced Mixing and Sensing.

Stirring small volumes of solution can reduce immunoassay readout time, homogenize cell cultures, and increase enzyme reactivity in bioreactors. However, at present many small scale stirring methods require external actuation, which can be cumbersome. To address this, here, reactive inkjet printing is shown to be able to produce autonomously rotating biocompatible silk-based microstirrers that can enhance fluid mixing. Rotary motion is generated either by release of a surface active agent (small molecular polyethylene glycol) resulting in Marangoni effect, or by catalytically powered bubble propulsion. The Marangoni driven devices do not require any chemicals to be added to the fluid as the "fuel," while the catalytically powered devices are powered by decomposing substrate molecules in solution. A comparison of Marangoni effect and enzyme powered stirrers is made. Marangoni effect driven stirrers rotate up to 600 rpm, 75-100-fold faster than enzyme driven microstirrers, however enzyme powered stirrers show increased longevity. Further to stirring applications, the sensitivity of the motion generation mechanisms to fluid properties allows the rotating devices to also be exploited for sensing applications, for example, acting as motion sensors for water pollution.

A Review of Curcumin and Its Derivatives as Anticancer Agents.

Cancer is the second leading cause of death in the world and one of the major public health problems. Despite the great advances in cancer therapy, the incidence and mortality rates of cancer remain high. Therefore, the quest for more efficient and less toxic cancer treatment strategies is still at the forefront of current research. Curcumin, the active ingredient of the Curcuma longa plant, has received great attention over the past two decades as an antioxidant, anti-inflammatory, and anticancer agent. In this review, a summary of the medicinal chemistry and pharmacology of curcumin and its derivatives in regard to anticancer activity, their main mechanisms of action, and cellular targets has been provided based on the literature data from the experimental and clinical evaluation of curcumin in cancer cell lines, animal models, and human subjects. In addition, the recent advances in the drug delivery systems for curcumin delivery to cancer cells have been highlighted.

Toxic effect of the novel chiral insecticide IPP and its biodegradation intermediate in nematode Caenorhabditis elegans.

Caenorhabditis elegans, a kind of model organism, was used to investigate biodegradation pathway of IPP and M1 in nematodes, in vivo toxicity from IPP and M1 and the possible underlying molecular mechanism. The results showed that both IPP and M1 could decrease lifespan, locomotion behavior, reproductive ability and AChE activity. During IPP biodegradation process, three intermediates (M1-M3) were monitored and identified. Based on the identified metabolites and their biodegradation courses, a possible biodegradation pathway was proposed. IPP was probably transformed to different three metabolites in nematodes through oxidation and elimination of methyl and propyl etc. Under the same concentration, IPP had more severe toxicity than M1 on nematodes. IPP and M1 might reduce lifespan and decrease reproductive ability through influencing insulin/IGF signaling pathway and TOR signaling pathway. They could decrease expression levels of daf-16, sgk-1, aak-2, daf-15 and rict-1 genes, which involved in IGF and TOR signaling pathway.

Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling.

Interfacial Adsorption of Silk Fibroin Peptides and Their Interaction with Surfactants at the Solid-Water Interface.

Regenerated silk fibroin (RSF) is a Food and Drug Administration-approved material and has been widely used in many biomedical and cosmetic applications. Because of the amphiphilic nature of the primary repeat amino acid sequence (e.g., AGAGAS), RSF peptides can significantly reduce the water surface tension and therefore have the potential to be used as a surface active component for many applications, particularly in the biomedical, cosmetic, pharmaceutical, and food industries. In this paper, the adsorption of RSF peptides separated into molecular fractions of 5-30, 30-300, and >300 kDa has been studied at the solid-water interface by neutron reflection and spectroscopic ellipsometry to assess its surface active behavior. A stable layer of RSF was found to be irreversibly adsorbed at the hydrophilic SiO2-water interface. Changes in solution concentration, pH, and ionic strength all had an impact on the final adsorbed amount found at the interface. There were no significant differences between the final adsorbed amounts or layer structure among the three RSF molecular fractions studied; however, >300 kDa RSF was more stable to changes in solution ionic strength. Adsorption of conventional anionic and cationic surfactants, sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (C12TAB), to the preadsorbed 5-30 kDa RSF revealed penetration of the surfactant into the RSF layer, at concentrations below the critical micellar concentration (CMC). SDS was found in the preadsorbed RSF layer and gradually removed RSF from the surface with an increase in SDS concentration. At concentrations above the CMC, there is near complete removal of RSF by SDS at the interface. C12TAB adsorbed into the preadsorbed RSF layer with considerably less removal of RSF from the interface compared to SDS. At concentrations above the CMC, both C12Tab and RSF were found to coexist at the interface, forming a less thick layer but with a considerable amount of RSF still present.

Synergistic effect of bioactive lipid and condition medium on cardiac differentiation of human mesenchymal stem cells from different tissues.

Human umbilical cord mesenchymal stem cells (hUCMSCs) and human adipose tissue mesenchymal stem cells (hATMSCs) have the potential to differentiate into cardiomyocytes, making them promising therapeutic candidates for treating damaged cardiac tissues. Currently, however, the differentiated cells induced from hUCMSCs or hATMSCs can hardly display functional characteristics similar to cardiomyocytes. In this study, we have investigated the effects of bioactive lipid sphingosine-1-phosphate (S1P) on cardiac differentiations of hUCMSCs and hATMSCs in condition medium composed of cardiac myocytes culture medium or 5-azacytidine. Cardiac differentiations were identified through immunofluorescence staining, and the results were observed with fluorescence microscopy and confocal microscopy. Synergistic effects of S1P and condition medium on cell viability were evaluated by MTT assays. Functional characteristics similar to cardiomyocytes were evaluated through detecting calcium transient. The differentiated hUCMSCs or hATMSCs in each group into cardiomyocytes showed positive expressions of cardiac specific proteins, including α-actin, connexin-43 and myosin heavy chain-6 (MYH-6). MTT assays showed that suitable differentiation time was 14 days and that the optimal concentration of S1P was 0.5 µM. Moreover, incorporation of S1P and cardiac myocytes culture medium gave rise to calcium transients, an important marker for displaying in vivo electrophysiological properties. This feature was not observed in the S1P-5-azacytidine group, indicating the possible lack of cellular stimuli such as transforming growth factor-beta, TGF-ß.

Co-adsorption of peptide amphiphile V(6)K and conventional surfactants SDS and C(12)TAB at the solid/water interface.

Recent research has reported many attractive benefits from short peptide amphiphiles. A practical route for them to enter the real world of applications is through formulation with conventional surfactants. This study reports the co-adsorption of the surfactant-like peptide, V6K, with conventional anionic and cationic surfactants at the solid/water interface. The time-dependant adsorption behaviour was examined using spectroscopic ellipsometry whilst adsorbed layer composition and structural distribution of the components were investigated by neutron reflection with the use of hydrogen/deuterium labelling of the surfactant molecules. Both binary (surfactant/peptide mixtures) and sequential (peptide followed by surfactant) adsorption have been studied. It was found that at the hydrophilic SiO2/water interface, the peptide was able to form a stable, flat, defected bilayer structure however both the structure and adsorbed amount were highly dependent on the initial peptide concentration. This consequently affected surfactant adsorption. In the presence of a pre-adsorbed peptide layer anionic sodium dodecyl sulfate (SDS) could readily co-adsorb at the interface; however, cationic dodecyl trimethyl ammonium bromide (C12TAB) could not co-adsorb due to the same charge character. However on a trimethoxy octyl silane (C8) coated hydrophobic surface, V6K formed a monolayer, and subsequent exposure to cationic and anionic surfactants both led to some co-adsorption at the interface. In binary surfactant/peptide mixtures, it was found that adsorption was dependent on the molar ratio of the surfactant and peptide. For SDS mixtures below molar unity and concentrations below CMC for C12TAB, V6K was able to dominate adsorption at the interface. Above molar unity, no adsorption was detected for SDS/V6K mixtures. In contrast, C12TAB gradually replaced the peptide and became dominant at the interface. These results thus elucidate the adsorption behaviour of V6K, which was found to dominate interfacial adsorption but its exact adsorbed amount and distribution were affected by interfacial hydrophobicity and interactions with conventional surfactants.

Interfacial structure of immobilized antibodies and perdeuterated HSA in model pregnancy tests measured with neutron reflectivity.

Experimental studies of antibody adsorption and antigen binding that mimicked pregnancy test immunoassays have been performed using neutron reflectivity studies of a model antibody/antigen system immobilized on the silica/water interface. The study revealed the nature of the antibody/antigen interaction and also the importance of a blocking protein, in this case human serum albumin (HSA), that enhances the immunoassay's specificity and efficiency. Of central importance to this study has been the use of a perdeuterated human serum albumin (d-HSA), providing contrast that highlights the orientation and position of the blocking agent within the adsorbed layer. It was found that the adsorbed HSA filled the gaps between the preadsorbed antibodies on the substrate, with decreased adsorption occurring as a function of increased antibody surface coverage. In addition, the antigen binding capacity of the adsorbed antibodies was investigated as a function of antibody surface coverage. The amount of specifically bound antigen was found to saturate at approximately 0.17 mg/m(2) and became independent of the antibody surface coverage. The ratio of bound antigen to immobilized antibody decreased with increased antibody surface coverage. These results are of importance for a full understanding of immunoassay systems that are widely used in clinical tests and in the detection of environmental contaminants.

Antimicrobial peptide A9K as a gene delivery vector in cancer cells.

Designed peptides are promising biomaterials for biomedical applications. The amphiphilic cationic antimicrobial peptide (AMP), A9K, can self-assemble into nano-rod structures and has shown cancer cell selectivity and could therefore be a promising candidate for therapeutic delivery into cancer cells. In this paper, we investigate the selectivity of A9K for cancer cell models, examining its effect on two human cancer cell lines, A431 and HCT-116. Little or no activity was observed on the control, human dermal fibroblasts (HDFs). In the cancer cell lines the peptide inhibited cellular growth through changes in mitochondrial morphology and membrane potential while remaining harmless towards HDFs. In addition, the peptide can bind to and protect nucleic acids while transporting them into both 2D cultures and 3D spheroids of cancer cells. A9K showed high efficiency in delivering siRNA molecules into the centre of the spheroids. A9K was also explored in vivo, using a zebrafish (Danio rerio) development toxicity assay, showing that the peptide is safe at low doses. Finally, a high-content imaging screen, using RNA interference (RNAi) targeted towards cellular uptake, in HCT-116 cells was carried out. Our findings suggest that active cellular uptake is involved in peptide internalisation, mediated through clathrin-mediated endocytosis. These new discoveries make A9K attractive for future developments in clinical and biotechnological applications.

Microfluidic formulation of food additives-loaded nanoparticles for antioxidation.

Browning has many important implications with nutrition and the shelf life of foods. Mitigating browning is of particular interest in food chemistry. The addition of antioxidants has been a common strategy to extend shelf life of drug and food products. In this work, we report a microfluidic technology for encapsulation of three common food additives (potassium metathionite (PMS), curcumin (CCM), and ß-carotene (ß-Car)) into nano-formulations using low-cost and readily available materials such as shellac. The food additives encapsulated nanoparticles provide a microenvironment that can prevent oxidation during daily storage. The results showed that the produced nanoparticles had a narrow size distribution with an average size of around 100 nm, were stable at conventional storage conditions (4 ºC) for 18 weeks, and had sustained release ability at 37 ºC, pH= 7.8, 160 rpm. In addition, further experiments showed that the formulation of hydrophobic additives, such as CCM and ß-Car did not only improve their bioavailability but also allowed for the encapsulation of a combination of ingredients. In addition, the antioxidants loaded nanoparticles demonstrated good biocompatibility, low toxicity to human cells. The longer release time of encapsulated food additives increases shelf life of foods and enhances consumer purchase preferences, which not only saves costs but also reduces waste. In summary, this study shows that such antioxidant-loaded nanoparticles provide a promising strategy in extending the shelf life of food products.

Stress fermentation strategies for the production of hyperthermostable superoxide dismutase from Thermus thermophilus HB27: effects of ions.

In this study, we explored how ammonium and metal ion stresses affected the production of recombinant hyperthermostable manganese superoxide dismutase (Mn-SOD). To improve Mn-SOD production, fed-batch culture in shake flasks and bioreactor fermentation were undertaken to examine the effects of [Formula: see text] and Mn(2+) feeding. Under the optimized feeding time and concentrations of [Formula: see text] and Mn(2+), the maximal SOD activity obtained from bioreactor fermentation reached some 480 U/ml, over 4 times higher than that in batch cultivation (113 U/ml), indicating a major enhancement of the concentration of Mn-SOD in the scale-up of hyperthermostable Mn-SOD production. In contrast, when the fed-batch culture with appropriate [Formula: see text] and Mn(2+) feeding was carried out in the same 5-L stirred tank bioreactor, a maximal SOD concentration of some 450 U/ml was obtained, again indicating substantial increase in SOD activity as a result of [Formula: see text] and Mn(2+) feeding. The isoelectric point (pI) of the sample was found to be 6.2. It was highly stable at 90 °C and circular dichroism measurements indicated a high α-helical content of 70 % as well, consistent with known SOD properties. This study indicates that [Formula: see text] and Mn(2+) play important roles in Mn-SOD expression. Stress fermentation strategies established in this study are useful for large-scale efficient production of hyperthermostable Mn-SOD and may also be valuable for the scale-up of other extremozymes.

Interfacial assembly of lipopeptide surfactants on octyltrimethoxysilane-modified silica surface.

The adsorption of a series of cationic lipopeptide surfactants, C14Kn (where C14 denotes the myristic acyl chain and Kn represents n number of lysine residues) at the hydrophobic solid/water interface has been studied using spectroscopic ellipsometry (SE) and neutron reflection (NR). The hydrophobic C8 surface was prepared by grafting a monolayer of octyltrimethoxysilane on the silicon surface. SE was used to follow the dynamic adsorption from these lipopeptide surfactants and the amount was found to undergo a fast increase within the first 2-3 min, followed by a much slower process tending to equilibration in the subsequent 15-20 min. Lipopetide surfactants with n = 1-4 showed similar dynamic features, indicating that the interaction between the acyl chain and the C8 surface is the main driving force for adsorption. The saturation adsorption amount of C14Kn at the C8/water interface was found to be inversely related to the increasing number of Lys residues in the head group due to the increase of steric hindrance and electrostatic repulsion between the head groups. Solution concentration had a significant effect on the initial adsorption rate, similar to the feature observed from nonionic surfactants CmEn. The structure of the adsorbed layers was studied by NR in conjunction with isotopic contrasts. The layer formed by the head groups of C14K1 was 10 Å thick, and those formed by C14K2, C14K3 and C14K4 head groups were all about 13 Å thick. In contrast, the thicknesses of the layers formed by hydrophobic tails of C14K1, C14K2 C14K3, and C14K4 were found to be 17, 13, 10, and 10 Å, respectively, resulting in the steady increase of area per molecule at the interface from 29 ± 2 Å(2) for C14K1 to 65 ± 2 Å(2) for C14K4. Thus, with an increase in the head group length, the molecules in the adsorbed layer tended to lie down upon adsorption.

3D culture of fibroblasts and neuronal cells on microfabricated free-floating carriers.

3D cell culture is a relatively recent trend in biomedical research for artificially mimicking in vivo environment and providing three dimensions for the cells to grow in vitro, particularly with regard to surface-adherent mammalian cells. Different cells and research objectives require different culture conditions which has led to an increase in the diversity of 3D cell culture models. In this study, we show two independent on-carrier 3D cell culture models aimed at two different potential applications. Firstly, micron-scale porous spherical structures fabricated from poly (lactic-co-glycolic acid) or PLGA are used as 3D cell carriers so that the cells do not lose their physiologically relevant spherical shape. Secondly, millimetre-scale silk fibroin structures fabricated by 3D inkjet bioprinting are used as 3D cell carriers to demonstrate cell growth patterning in 3D for use in applications which require directed cell growth. The L929 fibroblasts demonstrated excellent adherence, cell-division and proliferation on the PLGA carriers, while the PC12 neuronal cells showed excellent adherence, proliferation and spread on the fibroin carriers without any evidence of cytotoxicity from the carriers. The present study thus proposes two models for 3D cell culture and demonstrates, firstly, that easily fabricable porous PLGA structures can act as excellent cell carriers for aiding cells easily retain their physiologically relevant 3D spherical shape in vitro, and secondly, that 3D inkjet printed silk fibroin structures can act as geometrically-shaped carriers for 3D cell patterning or directed cell growth in vitro. While the 'fibroblasts on PLGA carriers' model will help achieve more accurate results than the conventional 2D culture in cell research, such as drug discovery, and cell proliferation for adoptive cell transfer, such as stem cell therapy, the 'neuronal cells on silk fibroin carriers' model will help in research requiring patterned cell growth, such as treatment of neuropathies.

Designed peptide amphiphiles as scaffolds for tissue engineering.

Peptide amphiphiles (PAs) are peptide-based molecules that contain a peptide sequence as a head group covalently conjugated to a hydrophobic segment, such as lipid tails. They can self-assemble into well-ordered supramolecular nanostructures such as micelles, vesicles, twisted ribbons and nanofibers. In addition, the diversity of natural amino acids gives the possibility to produce PAs with different sequences. These properties along with their biocompatibility, biodegradability and a high resemblance to native extracellular matrix (ECM) have resulted in PAs being considered as ideal scaffold materials for tissue engineering (TE) applications. This review introduces the 20 natural canonical amino acids as building blocks followed by highlighting the three categories of PAs: amphiphilic peptides, lipidated peptide amphiphiles and supramolecular peptide amphiphile conjugates, as well as their design rules that dictate the peptide self-assembly process. Furthermore, 3D bio-fabrication strategies of PAs hydrogels are discussed and the recent advances of PA-based scaffolds in TE with the emphasis on bone, cartilage and neural tissue regeneration both in vitro and in vivo are considered. Finally, future prospects and challenges are discussed.

Microfluidic formulation of anticancer peptide loaded ZIF-8 nanoparticles for the treatment of breast cancer.

Anticancer peptides (ACPs) are promising antitumor drugs owning to their great cancer cell targeting and anticancer effects as well as low drug resistance. However, many of the ACPs have non-specific toxicity and can be easily degraded by the enzymes after administration. Therefore, drug delivery systems (DDSs) are required to shield these peptides from degradation and induce targeted delivery. In this paper, a high performance microfluidic device was used to fabricate the zeolitic imidazolate framework (ZIF-8) encapsulating an ACP (At3) recently developed by our group. The microfluidic device allowed for efficient and rapid mixing to generate ACP loaded nanoparticles (NPs) with controllable properties at high production rate (120 mL/min) and high encapsulation efficiency. The ZIF-8 NPs synthesised by microfluidic processing showed lower polydispersity index (PDI) than the conventional method, demonstrating an improved size uniformity. Encapsulating At3 into the ZIF-8 (At3@ZIF-8) significantly reduced the hemolytic effect and provided a pH-controlled release of At3 peptide. At3@ZIF-8 showed higher anticancer effect than the unloaded peptide at the same concentration due to the enhanced cell uptake by the ZIF-8 NPs. The NPs were able to inhibit the growth of the multicellular tumour spheroids (MCTSs) and damage the mitochondrial membrane of the MCF-7 breast cancer cells. In vivo experiments demonstrated that the At3@ZIF-8 NPs inhibited the growth of MCF-7 tumours in nude mice without changing the biochemical properties of the blood or the histopathological properties of vital organs. Therefore, the development of At3 loaded NPs provides an alternative approach in ACP delivery which can broaden the application of ACP-based cancer therapy.