POxload: Machine Learning Estimates Drug Loadings of Polymeric Micelles.

Block copolymers, composed of poly(2-oxazoline)s and poly(2-oxazine)s, can serve as drug delivery systems; they form micelles that carry poorly water-soluble drugs. Many recent studies have investigated the effects of structural changes of the polymer and the hydrophobic cargo on drug loading. In this work, we combine these data to establish an extended formulation database. Different molecular properties and fingerprints are tested for their applicability to serve as formulation-specific mixture descriptors. A variety of classification and regression models are built for different descriptor subsets and thresholds of loading efficiency and loading capacity, with the best models achieving overall good statistics for both cross- and external validation (balanced accuracies of 0.8). Subsequently, important features are dissected for interpretation, and the DrugBank is screened for potential therapeutic use cases where these polymers could be used to develop novel formulations of hydrophobic drugs. The most promising models are provided as an open-source software tool for other researchers to test the applicability of these delivery systems for potential new drug candidates.

Tailored Monoacyl Poly(2-oxazoline)- and Poly(2-oxazine)-Lipids as PEG-Lipid Alternatives for Stabilization and Delivery of mRNA-Lipid Nanoparticles.

The successful use of lipid nanoparticles (LNPs) for clinical development of the COVID-19 mRNA vaccines marked a breakthrough in mRNA-LNP therapeutics. As one of the vital components of LNPs, poly(ethylene glycol)-lipid conjugates (PEG-lipids) influence particle biophysical properties and stability, as well as interactions within biological environments. Reports suggesting that anti-PEG antibodies can be detected quite commonly within the human population raise concerns that PEG content in commercial LNP products could further stimulate immune responses to PEG. The presence of anti-PEG antibodies has been linked to accelerated clearance of LNPs, potentially a source of variability in the biological response to mRNA-LNP products. This motivated us to explore potential PEG alternatives. Herein, we report physicochemical and biological properties of mRNA-LNPs assembled using poly(2-oxazoline) (POx)- and poly(2-oxazine) (POz)-based polymer-lipid conjugates. Notably, we investigated monoacyl lipids as alternatives to diacyl lipids. mRNA-LNPs produced using monoacyl POx/POz-lipids displayed comparable biophysical characteristics and cytocompatibility. Delivery of reporter mRNA resulted in similar transfection efficiencies, in both adherent and suspension cells, and in mice, compared to PEG-lipid equivalents. Our results suggest that monoacyl POx/POz-lipid-containing LNPs are promising candidates for the development of PEG-free LNP-based therapeutic products.

Nile red staining for rapid screening of plastic-suspect particles in edible seafood tissues.

Concerns regarding microplastic (MP) contamination in aquatic ecosystems and its impact on seafood require a better understanding of human dietary MP exposure including extensive monitoring. While conventional techniques for MP analysis like infrared or Raman microspectroscopy provide detailed particle information, they are limited by low sample throughput, particularly when dealing with high particle numbers in seafood due to matrix-related residues. Consequently, more rapid techniques need to be developed to meet the requirements of large-scale monitoring. This study focused on semi-automated fluorescence imaging analysis after Nile red staining for rapid MP screening in seafood. By implementing RGB-based fluorescence threshold values, the need for high operator expertise to prevent misclassification was addressed. Food-relevant MP was identified with over 95% probability and differentiated from natural polymers with a 1% error rate. Comparison with laser direct infrared imaging (LDIR), a state-of-the-art method for rapid MP analysis, showed similar particle counts, indicating plausible results. However, highly variable recovery rates attributed to inhomogeneous particle spiking experiments highlight the need for future development of certified reference material including sample preparation. The proposed method demonstrated suitability of high throughput analysis for seafood samples, requiring 0.02-0.06 h/cm2 filter surface compared to 4.5-14.7 h/cm with LDIR analysis. Overall, the method holds promise as a screening tool for more accurate yet resource-intensive MP analysis methods such as spectroscopic or thermoanalytical techniques.

Unravel the Tangle: Atomistic Insight into Ultrahigh Curcumin-Loaded Polymer Micelles.

Amphiphilic ABA-triblock copolymers, comprised of poly(2-oxazoline) and poly(2-oxazine), can solubilize poorly water-soluble molecules in a structure-dependent manner forming micelles with exceptionally high drug loading. All-atom molecular dynamics simulations are conducted on previously experimentally characterized, curcumin-loaded micelles to dissect the structure-property relationships. Polymer-drug interactions for different levels of drug loading and variation in polymer structures of both the inner hydrophobic core and outer hydrophilic shell are investigated. In silico, the system with the highest experimental loading capacity shows the highest number of drug molecules encapsulated by the core. Furthermore, in systems with lower loading capacity outer A blocks show a greater extent of entanglement with the inner B blocks. Hydrogen bond analyses corroborate previous hypotheses: poly(2-butyl-2-oxazoline) B blocks, found experimentally to have reduced loading capacity for curcumin compared to poly(2-propyl-2-oxazine), establish fewer but longer-lasting hydrogen bonds. This possibly results from different sidechain conformations around the hydrophobic cargo, which is investigated by unsupervised machine learning to cluster monomers in smaller model systems mimicking different micelle compartments. Exchanging poly(2-methyl-2-oxazoline) with poly(2-ethyl-2-oxazoline) leads to increased drug interactions and reduced corona hydration; this suggests an impairment of micelle solubility or colloidal stability. These observations can help driving forward a more rational a priori nanoformulation design.

Antifouling Properties of Poly(2-Oxazoline)s and Poly(2-Oxazine)s: Direct Comparison of Polymer-Coated Surfaces with the Same Coating Parameters.

This study presents a systematic comparison of the antifouling properties of water-soluble poly(2-oxazoline) (PAOx) and poly(2-oxazine) (PAOzi) brushes grafted to gold surfaces. PAOx and PAOzi are emerging polymer classes in biomedical sciences and are being considered superior alternatives to widely used polyethylene glycol (PEG). Four different polymers, poly(2-methyl-2-oxazoline) (PMeOx), poly(2-ethyl-2-oxazoline) (PEtOx), poly(2-methyl-2-oxazine) (PMeOzi), and poly(2-ethyl-2-oxazine) (PEtOzi), each of them in three different chain lengths, are synthesized and characterized for their antifouling properties. Results show that all polymer-modified surfaces display better antifouling properties than bare gold surfaces as well as analogous PEG coatings. The antifouling properties increase in the following order: PEtOx < PMeOx ≈ PMeOzi < PEtOzi. The study suggests that the resistance to protein fouling derives from both surface hydrophilicity and the molecular structural flexibility of the polymer brushes. PEtOzi brushes with moderate hydrophilicity show the best antifouling performance, possibly due to their highest chain flexibility. Overall, the research contributes to the understanding of antifouling properties in PAOx and PAOzi polymers, with potential applications in various biomaterials.

Synthesis, Characterization of NR@SiO2/PNIPAm-co-Ppa Composite Nanogel and Study On Its Application in Photodynamic Therapy.

In the present study, a novel composite nanogel based on fluorescence resonance energy transfer (FRET) and its application for photodynamic therapy is reported. First of all, nanoparticles of silica doped with Nile Red (NR) were prepared by Stöber method, then they were decorated by γ-methacryloxypropyltrimethoxysilane (MPS) to prepare MPS decorated NR@SiO2 nanoparticles, and finally they were copolymerized with N-isopropylacrylamide (NIPAm) and Pyropheophorbide-a (Ppa) by free radical copolymerization, and composite nanogel of NR@SiO2/PNIPAm-co-Ppa was fabricated. The microstructure of the as-prepared nanogel was characterized by Fourier transform infrared spectrum (FTIR), photoluminescence (PL), UV-Visible spectrophotometer (UV-Vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). PL spectrum indicated that, under irradiation of visible light source, energy can be transferred from NR to Ppa. UV-Vis spectrum demonstrated that aggregation of Ppa is prevented efficiently and Ppa exists as "monomer" state in the composite nanogel. Under irradiation of laser, singlet oxygen (1O2) can be produced efficiently by excited nanogel. The in vitro cytotoxicity test showed that HeLa cells can be killed by the composite nanogel.

Design and fabrication of a sensitive electrochemical sensor for uranyl ion monitoring in natural waters based on poly (brilliant cresyl blue).

New insights are proposed into enhancing detection of uranyl ions (UO22+) by electropolymerization brilliant cresyl blue-modified glassy carbon electrode (PBCB/GCE). The mercury-free PBCB/GCE sensor was applied to determine UO22+ in water samples by differential pulse adsorptive stripping voltammetry (DPAdSV). The unique combination of the PBCB/GCE and DPAdSV significantly improves sensitivity due to the polymer of high electroactive area and fast electron transfer rate. The DPAdSV current using a 3 mm diameter PBCB/GCE was proportional to the UO22+ concentration in the range 2.0-90.0 µg·L-1 (- 0.113 V vs. SCE) with a detection limit of 0.650 µg·L-1, RSD = 3.1% (n = 10), and 4.5% reproducibility. In addition, the sensitivity for UO22+ determination was further improved at using an 1 mm diameter PBCB/GCE, which enhances the efficiency of UO22+ deposition due to its higher current density. The 1 mm diameter PBCB/GCE based on DPAdSV technique could be used to determine uranyl ions in the concentration range 0.20-2.0 µg·L-1 (- 0.113 V vs. SCE) with a detection limit of 0.067 µg·L-1, RSD = 5.7 % (n = 10) and 5.4% reproducibility. Hence, the PBCB/GCE is a suitable candidate to substitute the mercury electrode. Graphical abstract.

Solubilization of Nile Red in Micelles and Protomicelles of Sodium Dodecyl Sulfate.

A spectrophotometric study of the solubilization and aggregation of the Nile red dye (NR) in premicellar and micellar aqueous solutions of sodium dodecyl sulfate (SDS) was carried out. The experiments were conducted both with saturated solutions of NR under conditions of thermodynamic equilibrium of the solution with a dye precipitate, and at a constant concentration of NR in a homogeneous solution. In the first case, it was proved theoretically and verified experimentally that with an increase in the SDS concentration, the NR concentration always increases, and at the limit of low concentrations, the dependence is linear. In both cases, the concentration of NR dimers as a function passes through a maximum in the premicellar region. There are no dimers in the micellar region. The extinction coefficients of NR monomers in SDS solutions were determined both below and above the critical micelle concentration (CMC) of SDS. A solubilization curve with branches for the premicellar and micellar regions was constructed, the intersection of which was used to find the CMC value in the system under study. The state of deep supersaturation of the NR solution in the metastable state upon dilution of the micellar system with water was studied. It was found that, in addition to dimers, molecular aggregates of higher orders were also formed.

Selective Removal of the Emerging Dye Basic Blue 3 via Molecularly Imprinting Technique.

A molecularly imprinting polymer (MIP) was synthesized for Basic Blue 3 dye and applied to wastewater for the adsorption of a target template. The MIPs were synthesized by bulk polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). Basic Blue 3 dye (BB-3), 2,2'-azobisisobutyronitrile (AIBN) and methanol were used as a functional monomer, cross linker, template, initiator and porogenic solvent, respectively, while non-imprinting polymers (NIP) were synthesized by the same procedure but without template molecules. The contact time was 25 min for the adsorption of BB-3 dye from 10 mL of spiked solution using 25 mg polymer. The adsorption of dye (BB-3) on the MIP followed the pseudo-second order kinetic (k2 = 0.0079 mg·g-1·min-1), and it was according to the Langmuir isotherm, with maximum adsorption capacities of 78.13, 85.4 and 99.0 mg·g-1 of the MIP at 283 K, 298 K and 313 K, respectively and 7 mg·g-1 for the NIP. The negative values of ΔG° indicate that the removal of dye by the molecularly imprinting polymer and non-imprinting polymer is spontaneous, and the positive values of ΔH° and ΔS° indicate that the process is endothermic and occurred with the increase of randomness. The selectivity of the MIP for BB-3 dye was investigated in the presence of structurally similar as well as different dyes, but the MIP showed higher selectivity than the NIP. The imprinted polymer showed 96% rebinding capacity at 313 K towards the template, and the calculated imprinted factor and Kd value were 10.73 and 2.62, respectively. In this work, the MIP showed a greater potential of selectivity for the template from wastewater relative to the closely similar compounds.

Thermoresponsive Polymer-Antibiotic Conjugates Based on Gradient Copolymers of 2-Oxazoline and 2-Oxazine.

A polymer-antibiotic conjugate with thermoresponsive properties near body temperature is presented. The backbone polymer is a copolymer of 2-n-propyl-2-oxazine (PropOzi) and methoxycarbonylethyl-2-oxazoline (C2MestOx) which is conjugated with the broad-spectrum antibiotic, cefazolin, via modification of the methyl ester group of C2MestOx. The resulting polymer-antibiotic conjugate has a cloud point temperature near body temperature, meaning that it can form a homogenous solution if cooled, but when injected into a skin-mimic at 37 °C, it forms a drug depot precipitate. Cleavage of the ester linker leads to quantitative release of the pristine cefazolin (with some antibiotic degradation observed) and redissolution of the polymer. When Escherichia coli were treated with polymer-antibiotic conjugate total clearance is observed within 12 h. The power of this approach is the potential for localized antibiotic delivery, for example, at a specific tissue site or into infected phagocytic cells.

Box-Behnken design aided optimization and validation of developed reverse phase HPLC analytical method for simultaneous quantification of dolutegravir sodium and lamivudine co-loaded in nano-liposomes.

A stability-indicating reversed-phase high-performance liquid chromatography method for simultaneous estimation of dolutegravir sodium and lamivudine encapsulated in the nanoliposomal formulation was developed. The chromatographic parameters namely, organic phase ratio, flow rate, and sample injection volume were selected as independent factors and were optimized by multivariate Box-Behnken design. Responses analyzed were retention time, peak area, and resolution. The optimized chromatographic method with Hypersil BDS C8 CN column as stationary phase and methanol and acetonitrile mixture and acidified Milli-Q water (pH 2.8, adjusted with 0.02% v/v orthophosphoric acid) as the mobile phase in an isocratic elution mode was validated according to parameters of International Conference on Harmonization Q1(R2) guidelines. The validated reversed-phase high-performance liquid chromatography method exhibited specificity for both dolutegravir sodium and lamivudine in the presence of degradation products as well as the liposomal matrix. This method was effectively utilized to determine the amount of drug entrapped and drug loading efficiency of dolutegravir sodium and lamivudine in a nano-liposomal formulation.

Enhanced Solubility and Bioavailability of Dolutegravir by Solid Dispersion Method: In Vitro and In Vivo Evaluation-a Potential Approach for HIV Therapy.

Being a candidate of BCS class II, dolutegravir (DTG), a recently approved antiretroviral drug, possesses solubility issues. The current research was aimed to improve the solubility of the DTG and thereby enhance its efficacy using the solid dispersion technique. In due course, the miscibility study of the drug was performed with different polymers, where Poloxamer 407 (P407) was found suitable to move forward. The solid dispersion of DTG and P407 was formulated using solvent evaporation technique with a 1:1 proportion of drug and polymer, where the solid-state characterization was performed using differential scanning calorimetry, Fourier transform infrared spectroscopy and X-ray diffraction. No physicochemical interaction was found between the DTG and P407 in the fabricated solid dispersion; however, crystalline state of the drug was changed to amorphous as evident from the X-ray diffractogram. A rapid release of DTG was observed from the solid dispersion (>95%), which is highly significant (p<0.05) as compared to pure drug (11.40%), physical mixture (20.07%) and marketed preparation of DTG (35.30%). The drug release from the formulated solid dispersion followed Weibull model kinetics. Finally, the rapid drug release from the solid dispersion formulation revealed increased Cmax (14.56 µg/mL) when compared to the physical mixture (4.12 µg/mL) and pure drug (3.45 µg/mL). This was further reflected by improved bioavailability of DTG (AUC: 105.99±10.07 µg/h/mL) in the experimental Wistar rats when compared to the AUC of animals administered with physical mixture (54.45±6.58 µg/h/mL) and pure drug (49.27±6.16 µg/h/mL). Therefore, it could be concluded that the dissolution profile and simultaneously the bioavailability of DTG could be enhanced by means of the solid dispersion platform using the hydrophilic polymer, P407, which could be projected towards improved efficacy of the drug in HIV/AIDS.

Enzyme Mimic Facilitated Artificial Cell to Mammalian Cell Signal Transfer.

Catalyzing biochemical reactions with enzymes and communicating with neighboring cells via chemical signaling are two fundamental cellular features that play a critical role in maintaining the homeostasis of organisms. Herein, we present an artificial enzyme (AE) facilitated signal transfer between artificial cells (ACs) and mammalian HepG2 cells. We synthesize metalloporphyrins (MPs) based AEs that mimic cytochrome P450 enzymes (CYPs) to catalyze a dealkylation and a hydroxylation reaction, exemplified by the conversion of resorufin ethyl ether (REE) to resorufin and coumarin (COU) to 7-hydroxycoumarin (7-HC), respectively. The AEs are immobilized in hydrogels to produce ACs that generate the two diffusive fluorophores, which can diffuse into HepG2 cells and result in dual intracellular emissions. This work highlights the use of AEs to promote AC to mammalian signal transfer, which opens up new opportunities for integrating the synthetic and living world with a bottom-up strategy.

Super-Resolution Imaging of Self-Assembled Nanocarriers Using Quantitative Spectroscopic Analysis for Cluster Extraction.

Self-assembled nanocarriers have inspired a range of applications for bioimaging, diagnostics, and drug delivery. The noninvasive visualization and characterization of these nanocarriers are important to understand their structure to function relationship. However, the quantitative visualization of nanocarriers in the sample's native environment remains challenging with the use of existing technologies. Single-molecule localization microscopy (SMLM) has the potential to provide both high-resolution visualization and quantitative analysis of nanocarriers in their native environment. However, nonspecific binding of fluorescent probes used in SMLM can introduce artifacts, which imposes challenges in the quantitative analysis of SMLM images. We showed the feasibility of using spectroscopic point accumulation for imaging in nanoscale topography (sPAINT) to visualize self-assembled polymersomes (PS) with molecular specificity. Furthermore, we analyzed the unique spectral signatures of Nile Red (NR) molecules bound to the PS to reject artifacts from nonspecific NR bindings. We further developed quantitative spectroscopic analysis for cluster extraction (qSPACE) to increase the localization density by 4-fold compared to sPAINT; thus, reducing variations in PS size measurements to less than 5%. Finally, using qSPACE, we quantitatively imaged PS at various concentrations in aqueous solutions with ∼20 nm localization precision and 97% reduction in sample misidentification relative to conventional SMLM.

Development of l-Amino-Acid-Based Hydroxyl Functionalized Biodegradable Amphiphilic Polyesters and Their Drug Delivery Capabilities to Cancer Cells.

Hydroxyl-functionalized amphiphilic polyesters based on l-amino acid bioresources were designed and developed, and their nanoassemblies were explored as intracellular enzyme-biodegradable scaffolds for delivering anticancer drugs and fluorophores to cancer cells. To accomplish this task, acetal-masked multifunctional dicarboxylic ester monomer from l-aspartic acid was tailor-made, and it was subjected to solvent-free melt transesterification polycondensation with commercial diols to produce acetal-functionalized polyesters. Acid-catalyzed postpolymerization deprotection of these acetal-polyesters produced amphiphilic hydroxyl-functionalized polyesters. The amphiphilic polyesters were self-assembled in aqueous medium to produce nanoparticles of size <200 nm. Wide ranges of both water-soluble and water-insoluble anticancer drugs such as doxorubicin (DOX), camptothecin (CPT), and curcumin (CUR) and fluorophores such as Nile red (NR), Rose Bengal (RB), and Congo red (CR) were encapsulated in hydroxyl polyesters nanoparticles. In vitro drug release studies revealed that the aliphatic polyester backbone underwent lysosomal enzymatic-biodegradation to release the loaded cargoes at the intracellular compartments. Lysotracker-assisted live-cell confocal microscopy studies further confirmed the colocalization of the polymer nanoscaffolds in the lysosomes and supported their enzymatic-biodegradation for drug delivery. In vitro cytotoxicity studies showed that the nascent polymers were not toxic, whereas their anticancer drug-loaded nanoparticles exhibited excellent cell killing in cervical cancer (HeLa) cell lines. The drug-loaded (CPT, CUR, and DOX) and the fluorophore-loaded (NR, RB, and CR) polymer nanoparticles were highly luminescent; thus, the encapsulated polymer nanoparticles enabled the multiple color-tunable bioimaging in cancer cells in the entire visible region from blue to deep red. Time-dependent live-cell confocal microscopy studies established that the cellular uptake of drugs and fluorophores was 5 to 10-fold higher while they were delivered from the hydroxyl polyester platform. The hydroxyl polyester nanocarrier design strategy opens up new opportunities in drug delivery to cancer cells from a biodegradable polymer platform based on l-amino acids.

Oxidative instability of boronic acid-installed polycarbonate nanoparticles.

Oxidative stress, caused by the overproduction of reactive oxygen species (ROS), is often observed in degenerative and/or metabolic diseases, tumors, and inflamed tissues. Boronic acids are emerging as a unique class of responsive biomaterials targeting ROS because of their reactivity toward H2O2. Herein, we examine the oxidative reactivity of nanoparticles from a boronic acid-installed polycarbonate. The extent of oxidation under different concentrations of H2O2 was tracked by the change in fluorescence intensity of an encapsulated solvatochromic reporter dye, demonstrating their sensitivity to biologically-relevant concentrations of hydrogen peroxide. Oxidation-triggered particle destabilization, however, was shown to be highly dependent on the concentration of the final oxidized polymer product, and was only achieved if it fell below polymer critical micelle concentration. Our results indicate that these nanocarriers serve as an excellent dual pH/H2O2 responsive vehicle for drug delivery.

Counterstaining to Separate Nile Red-Stained Microplastic Particles from Terrestrial Invertebrate Biomass.

The emerging threat that microplastic pollution poses to soil and its biota necessitates the development of methods to detect microplastic ingestion by soil animals. Fluorescent staining with Nile red dye has proven to be effective at distinguishing microplastics from inorganic and some biological material but is not suitable for separating them from invertebrate remains. Here, we report on the development and validation of a novel fluorescent counterstaining technique for detection of microplastics within terrestrial invertebrate biomass and fecal material. After being stained with a blend of Calcofluor white and Evans blue dyes in addition to Nile red, ground arthropod biomass appeared blueish-purple, whereas different plastic polymers appeared red, green, and yellow when viewed under laser scanning confocal microscopy. Nonarthropod invertebrate biomass and fecal material were also distinguishable from plastic, though to a lesser extent. Our results highlight the value of this method for detecting microplastic ingestion by terrestrial invertebrates.

A rapid chair-side method for the estimation of oral bacterial colonization density.

AIMS: Caries and periodontal disease are associated with inadequate control of oral bacteria. Since conventional microbiological evaluations are impractical in dental clinics or public engagement activities, a rapid test for the quantification of oral bacteria represents a useful tool. We describe the development of a colour change test to rapidly estimate bacterial colonisation density in the mouth. METHODS AND RESULTS: Volunteers rinsed with milk or milkshake. Viability indicators were added and colour changes quantified during incubation. Using milkshake and the resazurin-based solution PrestoBlue (9% v/v), the method distinguished between samples before and after brushing within 5 min. Colour changes were quantified and viable counts were obtained using oral rinses. Measured colour changes strongly correlated with total counts of both anaerobes and streptococci (Spearman's correlation coefficient of 0·782 and 0·769, respectively, P ≤ 0·001) and with perceived changes, as determined by volunteers (n = 10) visually ranking images. CONCLUSIONS: The resazurin milkshake test can rapidly and visually quantify viable bacteria in oral samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The resazurin milkshake test could serve as a sensitive semi-quantitative method for measuring oral bacteria in human oral rinse samples.

Chemical Signal Communication between Two Protoorganelles in a Lipid-Based Artificial Cell.

The chemical signal communication among organelles in the cell is extremely important for life. We demonstrate here the chemical signal communication between two protoorganelles using cascade enzyme reactions in a lipid-based artificial cell. Two protoorganelles inside the artificial cell are large unilamellar vesicles containing glucose oxidase (GOx-LUVs) and a vesicle containing horseradish peroxidase (HRP) and Amplex red, respectively. The glucose molecules outside the artificial cell penetrate the lipid bilayer through mellitin pores and enter into one protoroganelle (GOx-LUV) to produce H2O2, which subsequently is transported to the other protoorganelle to oxidize Amplex red into red resorufin catalyzed by HRP. The number of GOx-LUVs in an artificial cell is controlled by using a GOx-LUV solution with different density during the electroformation. The reaction rate for resorufin in the protoorganelle increases with more GOx-LUVs inside the artificial cell. The artificial cell developed here paves the way for a more complicated signal transduction mechanism study in a eukaryocyte.

Liposome production and concurrent loading of drug simulants by microfluidic hydrodynamic focusing.

Liposomes are spherical vesicles enclosed by phospholipid bilayers. Nanoscale liposomes are widely employed for drug delivery in the pharmaceutical industry. In this study, nanoscale liposomes are fabricated using the microfluidic hydrodynamic focusing (MHF) approach, and the effects of flow rate ratio (FRR) on liposome size and drug loading efficiency are studied. Fluorescein isothiocyanate modified dextran is used as a hydrophilic drug simulant and Nile red is used as a hydrophobic drug simulant. The experiment results show that hydrophilic drug simulant loading efficiency increases as FRR increases and eventually plateaues at around 90% loading efficiency. The hydrophobic drug simulant loading efficiency and FRR have a positive linear correlation when FRR varies from 10 to 50. Concurrent loading of both hydrophilic and hydrophobic drug simulants maintains the same loading efficiencies as those of loading each drug simulant alone. A negative correlation between liposome size and FRR is also confirmed. Unloaded liposomes and hydrophilic drug-loaded liposomes are of the same sizes, and are smaller than the ones loaded with the hydrophobic drug simulants alone or combined. The results suggest tunable liposome size and drug loading efficiency with the MHF technique. This provides evidence to encourage further studies of microfluidic liposome fabrication in the pharmaceutical industry.