Microfluidic formulation of lipid/polymer hybrid nanoparticles for plasmid DNA (pDNA) delivery

Development and applications of lipid hydrophilic headgroups for nucleic acid therapy

Nucleic acid therapy is currently the most promising method for treating tumors and genetic diseases and for preventing infectious diseases. However, the biggest obstacle to this therapy is delivery of the nucleic acids to the target site, which requires overcoming problems such as capture by the immune system, the need to penetrate biofilms, and degradation of nucleic acid performance. Designing suitable delivery vectors is key to solving these problems. Lipids-which consist of a hydrophilic headgroup, a linker, and a hydrophobic tail-are crucial components for the construction of vectors. The headgroup is particularly important because it affects the drug encapsulation rate, the vector cytotoxicity, and the transfection efficiency. Herein, we focus on various headgroup structures (tertiary amines, quaternary ammonium salts, peptides, piperazines, dendrimers, and several others), and we summarize and classify important lipid-based carriers that have been developed in recent years. We also discuss applications of cationic lipids with various headgroups for delivery of nucleic acid drugs, and we analyze how headgroup structure affects transport efficiency and carrier toxicity. Finally, we briefly describe the challenges of developing novel lipid carriers, as well as their prospects.

Production of 5-fluorouracil-loaded PLGA nanoparticles with toroidal microfluidic system and optimization of process variables by design of experiments

In recent decades, microfluidics has presented new opportunities for the production of nanoparticles (NPs). However, to achieve rapid clinical translation, the production of PLGA NPs in a single microfluidic channel for both the pharmaceutical research and industry without the need for scaling is still limited. The aim of this study was to accomplish the production of reproducible and stable 5-FU loaded Poly(lactic-co-glycolic acid) (PLGA) NPs, using an innovative toroidal microfluidic system, for cancer therapy. The toroidal microfluidic system enabled the production of spherical NPs ranging from 100 to 150 nm by adjusting both the TFR within the range of 5-15 mL/min and FRR between 1:3 and 1:7. A systematic assessment of critical process variables (total flow rate; TFR, flow rate ratio; FRR) for the production of PLGA NPs was conducted using Design of Experiment (DoE). The NPs, which exhibit a uniform size distribution, remained stable even after centrifugation and storage for 3 months at 4 °C. The encapsulation efficiency of drug and the concentration of NPs were not affected by changing process parameters. The effective 5-FU encapsulation into NPs resulted in a controlled in vitro drug release. Due to the controlled release profile of the 5-FU loaded PLGA NPs, the formulation was a promising candidate for mitigating the toxic side effects of free 5-FU and improving cancer treatment. In conclusion, toroidal microfluidic system enables high-volume production of stable PLGA NPs, both with and without 5-FU.

Conventional and microfluidic methods: Design and optimization of lipid-polymeric hybrid nanoparticles for gene therapy

Gene therapy holds significant promise as a therapeutic approach for addressing a diverse range of diseases through the suppression of overexpressed proteins and the restoration of impaired cell functions. Developing a nanocarrier that can efficiently load and release genetic material into cells remains a challenge. The primary goal of this study is to develop formulations aimed to enhance the therapeutic potential of GapmeRs through technological approaches. To this end, lipid-polymeric hybrid nanoparticles (LPHNPs) with PLGA, DC-cholesterol, and DOPE-mPEG2000 were produced by conventional single-step nanoprecipitation (SSN) and microfluidic (MF) methods. The optimized nanoparticles by SSN have a size of 149.9 ± 18.07 nm, a polydispersity index (PdI) of 0.23 ± 0.02, and a zeta potential of (ZP) of 29.34 ± 2.44 mV, while by MF the size was 179.8 ± 6.3, a PdI of 0.24 ± 0.01, and a ZP of 32.25 ± 1.36 mV. Furthermore, LPHNPs prepared with GapmeR-protamine by both methods exhibit a high encapsulation efficiency of approximately 90%. The encapsulated GapmeR is completely released in 24 h. The LPHNP suspensions are stable for up to 6 h in 10% FBS at pH 5.4 and 7.4. By contrast, LPHNPs remain stable in suspension in 4.5% albumin at pH 7.4 for 24 h. Additionally, LPHNPs were successfully freeze-dried using trehalose in the range of 2.5-5% as cryoprotectant The LPHNPs produced by MF and SSN increase, 6 and 12 fold respectively, GapmeR cell uptake, and both of them reduce by 60-70% expression of Tob1 in 48 h.Our study demonstrates the efficacy of the developed LPHNPs as carriers for oligonucleotide delivery, offering valuable insights for their scale up production from a conventional bulk methodology to a high-throughput microfluidic technology.

Microfluidic nanoprecipitation of PEGylated PLGA nanoparticles with rapamycin and performance evaluation

Rapamycin (RAP) is currently being developed as potential antibreast cancer drug. However, its poor solubility completely limits its use. The aim of this study was to develop polyethylene glycol-poly(lactide-co-glycolide) (PEG-PLGA)-based nanoparticles (NPs) to load RAP via microfluidics with an appropriate polyethylene glycol (PEG) content to enhance the bioavailability of RAP. Polydimethylsiloxane (PDMS) chips with a Y-shaped channel were designed to obtain RAP-loaded PEG-PLGA NPs (RAP-PEG-PLGA). The entrapment efficiency (EE) and drug loading (DL) as well as release profile of RAP-PEG-PLGA were evaluated, and their resistance to plasma albumin adsorption of NPs with different PEG contents was evaluated and compared. RAW264.7 and 4T1 cells were used to assess the antiphagocytic and anticancer cells effect of NPs, respectively. RAP-PEG-PLGA of around 124 nm in size were successfully prepared with the EE of 82.0% and DL of 12.3%, and sustained release for around 40 d. A PEG relative content of 10% within the PEG-PLGA molecule was shown superior in resisting protein adsorption. RAP-PEG-PLGA inhibited the growth of breast cancer cells when the concentration was over 10 μg/mL, and the inhibition efficiency was significantly higher than free RAP. Hence, the current RAP-PEG-PLGA could be a potential therapeutic system for breast cancer treatment.

Microfluidics produced ATRA-loaded PLGA NPs reduced tuberculosis burden in alveolar epithelial cells and enabled high delivered dose under simulated human breathing pattern in 3D printed head models

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is second only to COVID-19 as the top infectious disease killer worldwide. Multi-drug resistant TB (MDR-TB) may arise because of poor patient adherence to medications due to lengthy treatment duration and side effects. Delivering novel host directed therapies (HDT), like all trans retinoic acid (ATRA) may help to improve drug regimens and reduce the incidence of MDR-TB. Local delivery of ATRA to the site of infection leads to higher bioavailability and reduced systemic side effects. ATRA is poorly soluble in water and has a short half-life in plasma. Therefore, it requires a formulation step before it can be administered in vivo. ATRA loaded PLGA nanoparticles suitable for nebulization were manufactured and optimized using a scalable nanomanufacturing microfluidics (MF) mixing approach (MF-ATRA-PLGA NPs). MF-ATRA-PLGA NPs demonstrated a dose dependent inhibition of Mtb growth in TB-infected A549 alveolar epithelial cell model while preserving cell viability. The MF-ATRA-PLGA NPs were nebulized with the Aerogen Solo vibrating mesh nebulizer, with aerosol droplet size characterized using laser diffraction and the estimated delivered dose was determined. The volume median diameter (VMD) of the MF-ATRA-PLGA NPs was 3.00 ± 0.18 μm. The inhaled dose delivered in adult and paediatric 3D printed head models under a simulated normal adult and paediatric breathing pattern was found to be 47.05 ± 3 % and 20.15 ± 3.46 % respectively. These aerosol characteristics of MF-ATRA-PLGA NPs supports its suitability for delivery to the lungs via inhalation. The data generated on the efficacy of an inhalable, scalable and regulatory friendly ATRA-PLGA NPs formulation provides a foundation on which further pre-clinical testing can be built. Overall, the results of this project are promising for future research into ATRA loaded NPs formulations as inhaled host directed therapies for TB.

An update on strategies for optimizing polymer-lipid hybrid nanoparticle-mediated drug delivery: exploiting transformability and bioactivity of PLN and harnessing intracellular lipid transport mechanism

INTRODUCTION

Polymer-lipid hybrid nanoparticle (PLN) is an emerging nanoplatform with distinct properties and functionalities from other nanocarrier systems. PLN can be optimized to overcome various levels of drug delivery barriers to achieve desired therapeutic outcomes via rational selection of polymer and lipid combinations based on a thorough understanding of their properties and interactions with therapeutic agents and biological systems.

AREAS COVERED

This review provides an overview of PLN including the motive and history of PLN development, types of PLN, preparation methods, attestations of their versatility, and design strategies to circumvent various barriers for increasing drug delivery accuracy and efficiency. It also highlights recent advances in PLN design including: rationale selection of polymer and lipid components to achieve spatiotemporal drug targeting and multi-targeted cascade drug delivery; utilizing the intracellular lipid transport mechanism for active targeting to desired organelles; and harnessing bioreactive lipids and polymers to magnify therapeutic effects.

EXPERT OPINION

A thorough understanding of properties of PLN components and their biofate is important for enhancing disease site targeting, deep tumor tissue penetration, cellular uptake, and intracellular trafficking of PLN. For futuristic PLN development, active lipid transport and dual functions of lipids and polymers as both nanocarrier material and pharmacological agents can be further explored.

The development of DNA vaccines against SARS-CoV-2

BACKGROUND

The COVID-19 pandemic exerted significant impacts on public health and global economy. Research efforts to develop vaccines at warp speed against SARS-CoV-2 led to novel mRNA, viral vectored, and inactivated vaccines being administered. The current COVID-19 vaccines incorporate the full S protein of the SARS-CoV-2 Wuhan strain but rapidly emerging variants of concern (VOCs) have led to significant reductions in protective efficacies. There is an urgent need to develop next-generation vaccines which could effectively prevent COVID-19.

METHODS

PubMed and Google Scholar were systematically reviewed for peer-reviewed papers up to January 2023.

RESULTS

A promising solution to the problem of emerging variants is a DNA vaccine platform since it can be easily modified. Besides expressing whole protein antigens, DNA vaccines can also be constructed to include specific nucleotide genes encoding highly conserved and immunogenic epitopes from the S protein as well as from other structural/non-structural proteins to develop effective vaccines against VOCs. DNA vaccines are associated with low transfection efficiencies which could be enhanced by chemical, genetic, and molecular adjuvants as well as delivery systems.

CONCLUSIONS

The DNA vaccine platform offers a promising solution to the design of effective vaccines. The challenge of limited immunogenicity in humans might be solved through the use of genetic modifications such as the addition of nuclear localization signal (NLS) peptide gene, strong promoters, MARs, introns, TLR agonists, CD40L, and the development of appropriate delivery systems utilizing nanoparticles to increase uptake by APCs in enhancing the induction of potent immune responses.

Fabrication and Characterization of Electrospun Chitosan/Polylactic Acid (CH/PLA) Nanofiber Scaffolds for Biomedical Application

The present study demonstrates a strategy for preparing porous composite fibrous materials with superior biocompatibility and antibacterial performance. The findings reveal that the incorporation of PEG into the spinning solutions significantly influences the fiber diameters, morphology, and porous area fraction. The addition of a hydrophilic homopolymer, PEG, into the Ch/PLA spinning solution enhances the hydrophilicity of the resulting materials. The hybrid fibrous materials, comprising Ch modified with PLA and PEG as a co-solvent, along with post-treatment to improve water stability, exhibit a slower rate of degradation (stable, moderate weight loss over 16 weeks) and reduced hydrophobicity (lower contact angle, reaching 21.95 ± 2.17°), rendering them promising for biomedical applications. The antibacterial activity of the membranes is evaluated against Staphylococcus aureus and Escherichia coli, with PEG-containing samples showing a twofold increase in bacterial reduction rate. In vitro cell culture studies demonstrated that PEG-containing materials promote uniform cell attachment, comparable to PEG-free nanofibers. The comprehensive evaluation of these novel materials, which exhibit improved physical, chemical, and biological properties, highlights their potential for biomedical applications in tissue engineering and regenerative medicine.

Use of Microfluidics to Prepare Lipid-Based Nanocarriers

Lipid-based nanoparticles (LBNPs) are an important tool for the delivery of a diverse set of drug cargoes, including small molecules, oligonucleotides, and proteins and peptides. Despite their development over the past several decades, this technology is still hindered by issues with the manufacturing processes leading to high polydispersity, batch-to-batch and operator-dependent variability, and limits to the production volumes. To overcome these issues, the use of microfluidic techniques in the production of LBNPs has sharply increased over the past two years. Microfluidics overcomes many of the pitfalls seen with conventional production methods, leading to reproducible LBNPs at lower costs and higher yields. In this review, the use of microfluidics in the preparation of various types of LBNPs, including liposomes, lipid nanoparticles, and solid lipid nanoparticles for the delivery of small molecules, oligonucleotides, and peptide/protein drugs is summarized. Various microfluidic parameters, as well as their effects on the physicochemical properties of LBNPs, are also discussed.

Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy

Cancer-associated fibroblasts (CAFs) are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment, leading to the failure of triple-negative breast cancer (TNBC) immunotherapy. Therefore, depleting CAFs may enhance the effect of immunotherapy (such as PD-L1 antibody). Relaxin (RLN) has been demonstrated to significantly improve transforming growth factor-β (TGF-β) induced CAFs activation and tumor immunosuppressive microenvironment. However, the short half-life and systemic vasodilation of RLN limit its in vivo efficacy. Here, plasmid encoding relaxin (pRLN) to locally express RLN was delivered with a new positively charged polymer named polymeric metformin (PolyMet), which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before. In order to improve the stability of pRLN in vivo, this complex was further formed lipid poly-γ-glutamic acid (PGA)/PolyMet-pRLN nanoparticle (LPPR). The particle size of LPPR was 205.5 ± 2.9 nm, and the zeta potential was +55.4 ± 1.6 mV. LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1^luc/CAFs tumor spheres in vitro. In vivo, it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment, which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration. Thus, LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse, and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody (aPD-L1). Altogether, this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.