Every entry summarises what the study set out to test, what it found and why it changes how we design delivery systems. Browse research and reviews or search the collection.
A review of blood–brain barrier transport mechanisms and emerging lipid nanoparticle strategies for carrying nucleic acid and other complex therapies into the central nervous system.
This review surveys lipid nanoparticle composition, ionizable lipid synthesis and strategies to target delivery of fragile RNA therapeutics while addressing tissue selectivity and immune activation.
Ca Brimacombe, Ja Kulkarni, Mhy Cheng, K An, D Witzigmann, Pr Cullis
A review of the physical principles and development history behind siRNA lipid nanoparticles for liver gene silencing and mRNA lipid nanoparticles for protein expression.
Xuexiang Han, Ningqiang Gong, Lulu Xue, Margaret M. Billingsley, Rakan El-Mayta, Sarah J. Shepherd, Mohamad-Gabriel Alameh, Drew Weissman, Michael J. Mitchell
Liver fibrosis has no approved antifibrotic therapies. Activated hepatic stellate cells (HSCs) drive fibrosis by producing collagen, and HSP47 is a key collagen chaperone in these cells. Targeted delivery of siRNA to activated HSCs remains challenging, so a ligand-tethered LNP platform was developed to deliver RNA selectively to activated fibroblasts/HSCs. Lead AA-T3A-C12 LNP achieved >80% GFP knockdown at 50 nM in activated 3T3-GFP fibroblasts; knockdown significantly reduced by haloperidol (p = 0.009), confirming sigma receptor dependence. - In fibroblast/hepatocyte.
Yulia Eygieris, Mohit Gupta, Jeonghwan Kim, Gaurav Sahay
LNPs enabled the COVID-19 mRNA vaccines and the first siRNA-LNP drug, but there is still no one-size-fits-all LNP for every RNA therapeutic. A better chemistry-level understanding of LNP self-assembly, component roles, and whole-particle properties is needed to rationally design safer and more efficient RNA delivery systems. ## 3. Hypothesis / Central Thesis LNP performance is governed by the coordinated chemistry of ionizable lipids, sterols Ionizable lipids typically have tertiary amine headgroups and biodegradable ester linkers; cpKa ~9–10.5, LNP pKa ~6–7, and cLogD ~10–14 are associated with potency. - Cholesterol analogues can strongly.
Annabelle Biscans, Socheata Ly, Nicholas Mchugh, David A. Cooper, Anastasia Khvorova
Lipid-conjugated siRNAs can reach extrahepatic tissues, but silencing efficacy remains lower than in liver largely because only ~1–2% of internalized siRNA escapes endosomes into the cytoplasm. Ionizable lipids enhance endosomal escape in lipid nanoparticles (LNPs), but direct covalent conjugation of an ionizable lipid to siRNA had not been investigated. DLin-MC3-DMA conjugation retained RISC activity in vitro: IC50 values were 322 pM (unconjugated), 365 pM (cholesterol), and 481 pM (DLin-MC3-DMA). - Endosomal escape was enhanced: DLin-MC3-DMA-siRNA increased Gal8+.
Conventional chemotherapy suffers from poor targeting and severe side effects, while synthetic nanocarriers are often cleared by the immune system and lack precise tumor targeting. Cell membrane-coated nanocarriers (CMCNs) offer a biomimetic strategy to improve biocompatibility, immune evasion, circulation time, and homotypic tumor targeting. RBC membrane-coated PLGA nanocarriers improved blood retention to 72 hours vs 15.8 hours for typical PEGylated stealth nanocarriers. - Neutrophil membrane-coated nanocarriers showed 2–3-fold higher accumulation in.
RNA-loaded lipid nanoparticles (LNPs) are clinically validated for siRNA and mRNA delivery, but their therapeutic performance depends critically on reproducible control of size, size distribution, zeta potential, and RNA encapsulation efficiency. Microfluidic devices offer precise mixing, rapid ethanol dilution, high reproducibility, high-throughput formulation screening, and continuous production, making them attractive for standardized LNP. Increasing PEG-lipid from 1 to 5 mol% reduced siRNA-LNP size from 54 nm to 28 nm; DLin-KC2-DMA LNPs achieved 50% FVII silencing at 0.01 mg/kg in mice. - Optimized mRNA-LNP formulations improved delivery and expression.
Chemical Society Reviews* (as indicated by review format; exact volume/pages and DOI not included in the supplied file)2021ReviewNon-viral Gene Delivery
Yingshu Guo, Xiuping Cao, Xiaofei Zheng, Sk Jahir Abbas, Juan Li, Weihong Tan
Cancer treatment still relies heavily on chemotherapy, which causes severe damage to normal cells and systemic side effects. Safer, more selective drug delivery strategies are needed. Nanocarriers based on nucleic acids (NCNAs) are attractive because nucleic acids offer biocompatibility, low toxicity, programmable structures, controllable size, and modifiability—advantages that address limitations of cationic polymers, dendrimers, and inorganic nanoparticles. --- - DNA tetrahedron loaded with 5-fluorouracil: after 12 h co-incubation, the percentage of drug in cells was nearly 40%, demonstrating stable and efficient drug delivery. - DNA/RNA hybrid spherical nucleic acid with siRNA: rapidly absorbed by more than 60 kinds of cells; protected siRNA from enzymatic digestion and released it upon intracellular Dicer cleavage. - Se/Ru metal–organic nanoparticles + siRNA: enhanced cell uptake and promoted siRNA escape from endosomes/lysosomes, p
Michael J. Mitchell, Margaret M. Billingsley, Rebecca M. Haley, Marissa E. Wechsler, Nicholas A. Peppas, Robert Langer
Nanoparticle (NP) research has generated promising preclinical results, but clinical translation remains limited. A major barrier is the mismatch between one-size-fits-all NP designs and the heterogeneous biological barriers across patients and diseases. Precision medicine offers patient stratification, but precision therapies still face delivery barriers. This review argues that intelligent NP design can overcome these barriers and improve both general and precision therapeutic outcomes. --- - Tumor accumulation: Meta-analysis of 232 datasets found that, on average, only 0.7% of injected NP doses reach tumors. - EPR effect variability: Up to 10–15% of injected NPs accumulate at tumor sites in some studies, compared with 0.1% of free drug; however, EPR is highly heterogeneous. - Targeted NP limitation: Antibody-targeted NPs interacted with only 2% of tumor cells in one study. - iCluster system: Inhibited tumor growth by up to 95% in viv
Qurrat Ul Ain, Estefania V.R. Campos, Ariel Huynh, Dominik Witzigmann, Sarah Hedtrich
Gene therapies are powerful tools to prevent, treat, and cure human diseases, but their application to skin diseases has received little attention despite the easy accessibility of skin and urgent medical need. The main obstacle is the unique barrier properties of human skin, which severely limit absorption of biomacromolecules and efficient delivery of nucleic acid payloads. This review discusses current approaches, successes, and failures of cutaneous gene therapy and provides guidance for next-generation concepts, with delivery strategies as the major translational obstacle. --- - Skin barrier: Human skin efficiently absorbs only small molecules (MW < ~800 Da) with moderate lipophilicity (logP 1–3), making biomacromolecule delivery challenging. - Clinical trial landscape: Of 1052 gene therapy trials, only 23 focus on skin conditions; ~70% of ongoing gene therapy trials are viral vector-based. - LNP optimization: Zwitterionic lipid ce
Paula M. Cevaal, Abdalla Ali, Ewa Czuba-Wojnilowicz, Jori Symons, Sharon R. Lewin, Christina Cortez-Jugo, Frank Caruso
T cells are attractive targets for immunotherapy, cancer, HIV, autoimmunity, and inflammation, but nanoparticle delivery to T cells remains a major technological challenge due to their nonphagocytic nature and multiple physiological barriers. There is a need for rational design principles for in vivo T cell-targeting nanoparticles. --- - Barriers: Only ~2–3% of all T cells are in blood; <5% of administered nanoparticles typically reach target tissue; nanoparticles <~6 nm are renally cleared; T cells are nonphagocytic with low endocytosis rates; slow endosomal acidification in primary T cells can reduce pH-dependent cargo release. - Size rules: For receptor-mediated endocytosis (RME), optimum nanoparticle diameter ~50 nm; <200 nm preferred; >10 nm needed to avoid renal clearance; 10–100 nm ideal for lymph node delivery; <100 nm promotes escape from mononuclear phagocyte system scavenging. - Targeting outcomes: CD3-targeted PBAE/polygluta
Gene therapy requires safe, precise, efficient, and cost-effective delivery. Viral vectors are efficient but face manufacturing, cost, and safety challenges; non-viral vectors are safer and more scalable but often have low delivery efficiency. Magnetic nanoparticles (MNPs) have emerged as a promising strategy to enhance viral and non-viral gene delivery under an external magnetic field, while also enabling magnetic targeting, MRI tracking, and magnetic hyperthermia. --- - Magnetofection speed: MNP-based gene carriers can be attracted to cell surfaces in a few minutes, compared with hours for regular transfection. - Transfection enhancement: EMF enhanced lipid/SPIO-mediated transfection sixfold. PEI/Si@MNP with Dox and P-gp shRNA showed magnetically targeted delivery under 0.42 T for 12 h. - In vivo neuronal transfection: NeuroMag delivered EYFP-channelrhodopsin to rat visual cortex neurons with 72.66% and 86.63% expression at 3 and 30 d
Arun R. K. Kumar, Yufeng Shou, Brian Chan, Krishna L., Andy Tay
This review examines how viral vectors, electroporation, microfluidic systems, nanoparticles and high-aspect-ratio nanostructures can improve the efficiency, viability and scalability of transfecting primary immune cells for applications such as CAR-T, CAR-NK and gene editing. It highlights the trade-offs between delivery efficiency, cell fitness, cargo flexibility, manufacturing complexity and clinical translation.
Sarah J. Shepherd, Claude C. Warzecha, Sagar Yadavali, Rakan El-Mayta, Mohamad-Gabriel Alameh, Lili Wang, Drew Weissman, James M. Wilson, David Issadore, Michael J. Mitchell
Microfluidic mixing can produce precise LNPs but is limited in throughput, while bulk mixing is scalable but yields larger, heterogeneous particles with variable potency. A scalable microfluidic device is needed to produce potent RNA-LNPs across discovery and clinical scales. PMD achieved 18.4 L/h production, >100-fold higher throughput than a single microfluidic channel. - Mixing performance was uniform across 10× and 128× devices; 90% mixing channel length correlated linearly with ln(Pe).
Johan Karlsson, Stephanie Y. Tzeng, Shayan Hemmati, Kathryn M. Luly, Olivia Choi, Yuan Rui, David R. Wilson, Kristen L. Kozielski, Alfredo Quiñones-Hinojosa, Jordan J. Green
Systemic delivery of RNA therapeutics with polymer-based nanocarriers is limited by poor colloidal stability in blood and inefficient intracellular delivery of siRNA to the cytosol. There is a need for nanoparticles that remain stable extracellularly but rapidly release RNA intracellularly. Crosslinking: Molecular weight increased by 42.1% (Mn) and 27.7% (Mw); acrylate peak intensity decreased by 79.1% ± 0.3%. - Serum stability: XbNPs retained siRNA encapsulation in 50% serum; non-crosslinked formulations.
siRNA therapeutics are limited by poor cellular uptake, serum nuclease degradation, and inefficient endosomal/lysosomal escape. Chitosan is biocompatible and biodegradable but has low transfection efficiency, largely due to poor buffering capacity and weak endosomal escape. Histidine grafting was explored to add imidazole groups (pKa ~6) that enhance proton-sponge buffering and siRNA delivery. Synthesis: FT-IR showed amide C=O at 1640 cm⁻¹ and N–H bending shift from 1590 to 1522 cm⁻¹; histidine O–H at 3016 cm⁻¹ disappeared. XRD showed loss of histidine crystal peaks at 18.8° and 24.3°, and HGCS polymers were.
Synthetic nanoparticles face physiological barriers, RES clearance, and unintended biological interactions despite PEGylation and ligand grafting. Biological vectors—cell membranes, extracellular vesicles (EVs), and viruses—offer biocompatibility, biodegradability, immune evasion, and natural targeting. This review summarizes BNPs integrating biological vectors with functional agents for targeted delivery in imaging and therapy. RBCM-coated PLGA nanoparticles improved half-life by ~50% vs PEGylated nanoparticles and were detected in circulation after 72 h. - NM-NP-CFZ (neutrophil membrane-coated carfilzomib PLGA NPs) reduced lung metastasis by.
Mandana T. Manzari, Yosi Shamay, Hiroto Kiguchi, Neal Rosen, Maurizio Scaltriti, And Daniel A. Heller
Precision medicine has transformed cancer therapy by enabling molecular profiling and optimized drug design, but clinical translation of many precision therapeutics is hindered by pharmacological limitations, including toxicities and drug resistance. Drug delivery materials can modulate a drug’s pharmacokinetics, biodistribution, and toxicity without compromising its molecular target engagement, offering a route to improve the therapeutic index. Kinase inhibitor landscape: More than 50 small-molecule protein kinase inhibitors have been FDA-approved, with the majority developed as targeted cancer therapeutics. - Dose-limiting toxicity example: In a phase I trial.
RNA therapeutics—ASOs, siRNAs, miRNAs, mRNAs, and CRISPR-Cas9 sgRNAs—are limited by nuclease degradation, large size, and negative charge. Ionizable lipids are the key LNP component that condenses RNA, enables endosomal escape, and reduces toxicity. Since 2008, many ionizable lipids have been created, but the field lacks systematic categorization to guide next-generation design. MC3 is used in the FDA-approved siRNA drug Onpattro (patisiran) for hereditary transthyretin amyloidosis. - Optimized C12-200 formulation increased mRNA expression 7-fold vs standard formulation. - 7C1 achieved ~80%.
Schlich M, Palomba R, Costabile G, Mizrahy S, Pannuzzo M, Peer D, Decuzzi P
Endosomal escape remains the major intracellular barrier for RNA therapeutics. Only a small fraction of RNA delivered by ionizable lipid nanoparticles (LNPs) reaches the cytosol, where siRNA, miRNA, mRNA, and CRISPR components must act. A deeper mechanistic understanding is needed to design next-generation LNPs with improved cytosolic delivery. Only 1–2% of siRNA delivered by MC3-LNPs was visualized in the cytosol in one key study; another estimated ~3.5% cytosolic release. - Endosomal escape occurs in a narrow time window from a hybrid early/late endosome.
Rumiana Tenchov, Robert E. Bird, Allison E. Curtze, Qiongqiong Angela Zhou
Lipid nanoparticles (LNPs) have become key delivery vehicles across pharmaceuticals, with renewed prominence as the delivery platform for COVID-19 mRNA vaccines. The field lacks a broad, quantitative landscape of LNP research across liposomes, solid lipid nanoparticles, nanostructured lipid carriers, cationic lipid–nucleic acid complexes, and newer architectures. This review provides an overview of LNP structures, properties, applications, and. LNP research is dominated by pharmaceutical applications. The fastest-growing research areas are pharmaceuticals, food and feed, and cosmetics. - The term “liposome” appears in ~147,000 documents from 2000–2020, versus.
Matthew R. Aronson, Scott H. Medina, Michael J. Mitchell
Most clinically approved cancer therapies are potent and toxic small molecules limited by severe off-target toxicities and poor tumor-specific localization. Liposomal encapsulation reduces toxicity, but reliance on passive targeting via the enhanced permeability and retention (EPR) effect leaves unresolved issues such as heterogeneous tumor accumulation. Peptide-functionalized liposomes offer an active targeting strategy for receptor-mediated. TfR-targeting T7: D-enantiomer T7 showed increased binding affinity over L-T7 and transferrin; T7-liposomes loaded with docetaxel significantly reduced tumor growth in mice. T7-quercetin liposomes increased cytotoxicity.
Cancer immunotherapy can produce durable clinical responses, but systemic delivery of immunostimulatory agents is limited by short half-lives, off-target toxicities (e.g., cytokine release syndrome), low response rates (10–30%), and poor efficacy in solid tumors. Polymeric micelles offer a biocompatible, modifiable, core–shell delivery platform that can improve bioavailability, enable tumor accumulation via the EPR effect, and reduce systemic. IL-2 micelles: Enhanced DC vaccine efficacy and increased antigen-specific CTL accumulation at tumor sites. - PMet-P(cdmPEG2K) micelles: Co-delivery of DOX and pIL-12 was more effective at inhibiting tumor growth than.
