Amphiphilic AIE Fluorescent Probe: A Dual-Functionality Strategy for Efficient Antibacterial Therapy Fluorescence Bioimaging against Staphylococcus aureus.

Drug-resistant bacteria present a grave threat to human health. Fluorescence imaging-guided photodynamic antibacterial therapy holds enormous potential as an innovative treatment in antibacterial therapy. However, the development of a fluorescent material with good water solubility, large Stokes shift, bacterial identification, and high photodynamic antibacterial efficiency remains challenging. In this study, we successfully synthesized an amphiphilic aggregation-induced emission (AIE) fluorescent probe referred to as NPTPA-QM. This probe possesses the ability to perform live-bacteria fluorescence imaging while also exhibiting antibacterial activity, specifically against Staphylococcus aureus (S. aureus). We demonstrate that NPTPA-QM can eliminate S. aureus at a very low concentration (2 µmol L-1). Moreover, it can effectively promote skin wound healing. Meanwhile, this NPTPA-QM exhibits an excellent imaging ability by simple mixing with S. aureus. In summary, this research presents a straightforward and highly effective method for creating "amphiphilic" AIE fluorescent probes with antibacterial properties. Additionally, it offers a rapid approach for imaging bacteria utilizing red emission.

Recent Advances in Zein-Based Nanocarriers for Precise Cancer Therapy.

Cancer has emerged as a leading cause of death worldwide. However, the pursuit of precise cancer therapy and high-efficiency delivery of antitumor drugs remains an enormous obstacle. The major challenge is the lack of a smart drug delivery system with the advantages of biodegradability, biocompatibility, stability, targeting and response release. Zein, a plant-based protein, possesses a unique self-assembly ability to encapsulate anticancer drugs directly or indirectly. Using zein as a nanotherapeutic pharmaceutic preparation can protect anticancer drugs from harsh environments, such as sunlight, stomach acid and pepsin. Moreover, the surface functionalization of zein is easily realized, which can endow it with targeting and stimulus-responsive release capacity. Hence, zein is an ideal nanocarrier for the precise delivery of anticancer drugs. Combined with our previous research experiences, we attempt to review the current state of the preparation of zein-based nanocarriers for anticancer drug delivery. The challenges, solutions and development trends of zein-based nanocarriers for precise cancer therapy are discussed. This review will provide a guideline for precise cancer therapy in the future.

A Novel Aggregation-Induced Emission Fluorescent Probe for Detection of ß-Amyloid Based on Pyridinyltriphenylamine and Quinoline-Malononitrile.

ß-amyloid is an important pathological feature of Alzheimer's disease. Its abnormal production and aggregation in the patient's brain is an important basis for the early diagnosis and confirmation of Alzheimer's disease. In this study, a novel aggregation-induced emission fluorescent probe, PTPA-QM, was designed and synthesized based on pyridinyltriphenylamine and quinoline-malononitrile. These molecules exhibit a donor-donor-π-acceptor structure with a distorted intramolecular charge transfer feature. PTPA-QM displayed the advantages of good selectivity toward viscosity. The fluorescence intensity of PTPA-QM in 99% glycerol solution was 22-fold higher than that in pure DMSO. PTPA-QM has been confirmed to have excellent membrane permeability and low toxicity. More importantly, PTPA-QM exhibits a high affinity towards ß-amyloid in brain sections of 5XFAD mice and classical inflammatory cognitive impairment mice. In conclusion, our work provides a promising tool for the detection of ß-amyloid.

Zein-based nanoparticles: Preparation, characterization, and pharmaceutical application.

Zein, as one of the natural and GRAS proteins in plant, is renewable, nontoxic, biocompatible and biodegradable. Over the past decade, many research efforts have been devoted to zein-based biomaterials for several industrial applications. Combining with research experiences in our research group, the preparation methods, characterizations and pharmaceutical applications of zein-based nanoparticles were summarized in this review. Zein NPs with different particle nanostructures have been prepared by chemical crosslinking, desolvating, dispersing and micromixing strategies. The pharmaceutical applications of zein NPs are mainly focus on the drug delivery. Zein NPs can improve the drug stability, increase the oral bioavailability, control the drug release and enhance the drug targeting, thereby improving the pharmaceutical effect effectively. More efforts are required to analyze the relationship among preparation methods, particle nanostructures and pharmaceutical properties in virtue of quality by design approach, and further promote the scale-up production and clinical application of zein NPs.

Development of carboxymethyl chitosan-coated zein/soy lecithin nanoparticles for the delivery of resveratrol.

The objective of this work is to formulate a zein-based nanocomposite for the delivery of natural polyphenols. A proprietary atomizing/antisolvent precipitation (AAP) process was used to prepare carboxymethyl chitosan (CMC)-coated zein/soy lecithin (SL) nanoparticles (ZLC NPs). At a suitable mass ratio of zein/SL/CMC (100 : 30 : 30), ZLC NPs with desirable redispersibility and physicochemical stability were successfully fabricated. After that, resveratrol (Res) as the representative natural polyphenol was encapsulated in ZLC NPs. The optimized Res/ZLC NPs exhibited a spherical morphology, small size (259.43 ± 2.47 nm), large zeta potential (-47.7 ± 0.66 mV), and high encapsulation efficiency (91.32 ± 4.01%) and loading capacity (5.27 ± 0.35%). Further characterization indicated that Res was encapsulated in the hydrophobic core of the ZLC matrix in an amorphous state. Compared to free Res, Res/ZLC NPs showed a 2.55-fold increase in the Res dissolution rate, a 2.27-fold increase in bioaccessibility, and a 1.69-fold increase in ABTS˙+ scavenging activity. Also, Res/ZLC NPs showed a higher Res retention rate (>68.0%) than free Res (<35.0%) over 45 days of storage. Therefore, ZLC NPs have promising potential as vehicles for natural polyphenols.

Development of a Method for Fast Assessment of Protein Solubility Based on Ultrasonic Dispersion and Differential Centrifugation Technology.

Protein solubility is very important for protein crystallization, bioprocess development, and protein application. In this study, a method based on the stability of a protein dispersion system is proposed for fast assessment of protein solubility, which mainly involves ultrasonic dispersion, differential centrifugation, and spectral measurement (UDDCS) and curvature estimation. The appropriate ultrasonic time and centrifugal time were experimentally determined at first. The results show that the relationship between the standard deviation and the protein concentrations originally added accords with the modified exponential equation, and the corresponding concentration of the maximum curvature point is defined as the solubility of the protein. Lysozyme solubility data in NaCl aqueous solutions and zein solubility data in ethanol aqueous solutions are selected to verify the UDDCS method by comparing the data obtained by the UDDCS method and the results from references, and the results indicate that the UDDCS method is reliable, universal, and time-saving. Finally, measurements of zein solubility in NaOH solution and casein solubility in urea aqueous solution were conducted as test cases by the UDDCS method.

Rational Fabrication of Folate-Conjugated Zein/Soy Lecithin/Carboxymethyl Chitosan Core-Shell Nanoparticles for Delivery of Docetaxel.

The objective of this work is to design and fabricate a natural zein-based nanocomposite with core-shell structure for the delivery of anticancer drugs. As for the design, folate-conjugated zein (Fa-zein) was synthesized as the inner hydrophobic core; soy lecithin (SL) and carboxymethyl chitosan (CMC) were selected as coating components to form an outer shell. As for fabrication, a novel and appropriate atomizing/antisolvent precipitation process was established. The results indicated that Fa-zein/SL/CMC core-shell nanoparticles (FZLC NPs) were successfully produced at a suitable mass ratio of Fa-zein/SL/CMC (100:30:10) and the freeze-dried FZLC powder showed a perfect redispersibility and stability in water. After that, docetaxel (DTX) as a model drug was encapsulated into FZLC NPs at different mass ratios of DTX to FZLC (MR). When MR = 1:15, DTX/FZLC NPs were obtained with high encapsulation efficiency (79.22 ± 0.37%), small particle size (206.9 ± 48.73 nm), and high zeta potential (-41.8 ± 3.97 mV). DTX was dispersed in the inner core of the FZLC matrix in an amorphous state. The results proved that DTX/FZLC NPs could increase the DTX dissolution, sustain the DTX release, and enhance the DTX cytotoxicity significantly. The present study provides insight into the formation of zein-based complex nanocarriers for the delivery of anticancer drugs.

Effects of Surfactants on Zein Cast Films for Simultaneous Delivery of Two Hydrophilic Active Components.

In order to prepare edible films with outstanding antimicrobials and antioxidants utilized in applications of food and pharmaceutics, in this study, effects of surfactants on zein cast films for simultaneous delivery of lysozyme (LY) and ascorbic acid (AA) were investigated, where sodium alginate (SA), soy lecithin (SL), and Pluronic f-68 (PF-68) were selected as surfactants. FT-IR tests indicated that SL or PF-68 dramatically changed secondary structure of zein composite films, which heightened the irregularity of the composite film and inhibited LY crystallization. Mechanical tests showed that highly flexible films exhibiting elongations between 129% and 157% were obtained when adding PF-68. Compared with the film without emulsifier, zein film containing SL and PF-68 showed approximately 7.51 and 0.55 times lower initial release rates for LY and AA respectively, which significantly improved the controlled release and heightened the anti-microbial and anti-oxidant activities of the film. Finally, emulsified mechanisms of the surfactants in zein films were proposed.

Applications of Supercritical Anti-Solvent Process in Preparation of Solid Multicomponent Systems.

Solid multicomponent systems (SMS) are gaining an increasingly important role in the pharmaceutical industry, to improve the physicochemical properties of active pharmaceutical ingredients (APIs). In recent years, various processes have been employed for SMS manufacturing. Control of the particle solid-state properties, such as size, morphology, and crystal form is required to optimize the SMS formulation. By utilizing the unique and tunable properties of supercritical fluids, supercritical anti-solvent (SAS) process holds great promise for the manipulation of the solid-state properties of APIs. The SAS techniques have been developed from batch to continuous mode. Their applications in SMS preparation are summarized in this review. Many pharmaceutical co-crystals and solid dispersions have been successfully produced via the SAS process, where the solid-state properties of APIs can be well designed by controlling the operating parameters. The underlying mechanisms on the manipulation of solid-state properties are discussed, with the help of on-line monitoring and computational techniques. With continuous researching, SAS process will give a large contribution to the scalable and continuous manufacturing of desired SMS in the near future.

Development of nimesulide amorphous solid dispersions via supercritical anti-solvent process for dissolution enhancement.

Formulating amorphous solid dispersions (ASDs) is one of the most promising strategies to overcome solubility limitations in drug development. In this work, development of nimesulide (NIM) ASDs via supercritical anti-solvent (SAS) process was proposed, where the mixtures of dichloromethane (DCM) and methanol (MeOH) were selected as the liquid solvent, and the mixtures of hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) were the dispersing materials. The effects of NIM/HPMC/PVP (w/w/w) ratio and DCM/MeOH (v/v) ratio on particle solid-state properties were investigated to identify successful operating conditions. NIM-ASDs powders were formed by well separated spherical microparticles, where NIM crystals had transformed into amorphous state completely; the production yield was 93.6 ± 1.14%; and the reproducibility was very high. For NIM-ASDs, intermolecular interactions between NIM and dispersing materials were formed; the residual solvent was far below the ICH limit; and the chemical structure of NIM did not be degraded or disrupted. Moreover, NIM-ASDs increased the NIM solubility in PBS (pH=6.8) more than 5-folds; the dissolution of NIM from NIM-ASDs granules was faster and more complete than that from commercial Aulin® granules in PBS (pH=6.8). Also, NIM-ASDs well hindered the aging in the recrystallization of amorphous NIM during 12-month sealed storage. Overall, development of NIM-ASDs via SAS process presents an opportunity that as a modified product to increase the efficacy of NIM.

Design of gefitinib-loaded poly (l-lactic acid) microspheres via a supercritical anti-solvent process for dry powder inhalation.

To develop a safer, more stable and potent formulation of gefitinib (GFB), micro-spheres of GFB encapsulated into poly (l-lactic acid) (PLLA) have been prepared by supercritical anti-solvent (SAS) technology in this study. Operating factors were optimized using a selected OA16 (45) orthogonal array design, and the properties of the raw material and SAS processed samples were characterized by different methods The results show that the GFB-loaded PLLA particles prepared were spherical, having a smaller and narrower particle size compared with raw GFB. The optimal GFB-loaded PLLA sample was prepared with less aggregation, highest GFB loading (15.82%) and smaller size (D50=2.48µm, which meets the size of dry powder inhalers). The results of XRD and DSC indicate that GFB is encapsulated into PLLA matrix in a polymorphic form different from raw GFB. FT-IR results show that the chemical structure of GFB does not change after the SAS process. The results of in vitro release show that the optimal sample release was slower compared with raw GFB particles. Moreover, the results of in vitro anti-cancer trials show that the optimal sample had a higher cytotoxicity than raw GFB. After blending with sieved lactose, the flowability and aerosolization performance of the optimal sample for DPI were improved, with angle of repose, emitted dose and fine particles fractions from 38.4° to 23°, 63.21% to >90%, 23.37% to >30%, respectively.

In vitro and in vivo anti-tumor efficacy of 10-hydroxycamptothecin polymorphic nanoparticle dispersions: shape- and polymorph-dependent cytotoxicity and delivery of 10-hydroxycamptothecin to cancer cells.

Nanotechnology associated with a crystal engineering approach was proposed for improving the solubility and efficacy of hydrophobic drugs in this study. 10-hydroxycamptothecin polymorphic nanoparticle dispersions (HCPT-PNDs) were prepared using the supercritical anti-solvent technique coupled with the high-pressure homogenization method. Shape- and polymorph-dependent tumor suppression was observed in both in vitro and in vivo models, where needle-shaped HCPT-PND exhibited dramatic improvement of antitumor efficacy. A benefit of controllable size and a large surface-to-volume ratio of needle-shaped nanoparticles is the improvement of dissolution properties, which facilitates enhancing pharmacokinetic and pharmaco-dynamic properties. The needle-shaped HCPT-PND, which with longer blood retention time and more effective cellular uptake, makes it possible to accumulate drug in tumor tissues and exhibit higher cytotoxicity. No severe systemic toxicity was observed due to sustained-dissolution and the low dose of drug in normal tissues. The results suggest that the needle-shaped HCPT-PND is an interesting nano-formulation of HCPT. FROM THE CLINICAL EDITOR: Nanotechnology has enabled the production of novel therapeutics drugs against cancer. Here, the authors investigated the use of a crystal engineering approach for the modification of camptothecin in order to improve its water solubility. Physicochemical and biological properties were studied. The results would suggest the applicability of this approach for nano-formulation.

New polymorphs of 9-nitro-camptothecin prepared using a supercritical anti-solvent process.

Recrystallization and micronization of 9-nitro-camptothecin (9-NC) has been investigated using the supercritical anti-solvent (SAS) technology in this study. Five operating factors, i.e., the type of organic solvent, the concentration of 9-NC in the solution, the flow rate of 9-NC solution, the precipitation pressure and the temperature, were optimized using a selected OA16 (4(5)) orthogonal array design and a series of characterizations were performed for all samples. The results showed that the processed 9-NC particles exhibited smaller particle size and narrower particle size distribution as compared with 9-NC raw material (Form I), and the optimum micronization conditions for preparing 9-NC with minimum particle size were determined by variance analysis, where the solvent plays the most important role in the formation and transformation of polymorphs. Three new polymorphic forms (Form II, III and IV) of 9-NC, which present different physicochemical properties, were generated after the SAS process. The predicted structures of the 9-NC crystals, which were consistent with the experiments, were performed from their experimental XRD data by the direct space approach using the Reflex module of Materials Studio. Meanwhile, the optimal sample (Form III) was proved to have higher cytotoxicity against the cancer cells, which suggested the therapeutic efficacy of 9-NC is polymorph-dependent.

Tailoring Particle Microstructures via Supercritical CO2 Processes for Particular Drug Delivery.

Strategies for a particular drug delivery are always of great interest to the pharmaceutical industry, and efficient methods of preparing products with controlled particle microstructures are fundamental for the development and application of drug delivery. Supercritical fluid particle design (SCF PD) processes, as a green and effective alternative to traditional methods, have been effectively employed to produce particles with designated microstructures. Combining with research experiences in our research group, this review aims to provide a roadmap of SCF PD for particular drug delivery. For any drug delivery formulations, macroscopic properties (administration methods, drug release behaviour and targeting) are directly influenced by the particle microstructures (morphology, particle size, particle size distribution, crystal form, drug loading, encapsulation efficiency, etc). "Inverse" strategies are introduced at first to obtain the necessary particle microstructures for a particular drug delivery in this paper. Then, how to produce particles with designated microstructures via SCF PD processes is discussed, mainly focusing on the screening and selection of operating parameters according to thermodynamic and fluid dynamic studies. Recent examples of SCF micronization and co-precipitation/encapsulation processes are also summarized with an emphasis on how to tailor the particle microstructures by controlling the operating parameters. Finally, challenges and issues needing further study are briefly suggested for SCD PD.