Nanoparticle delivery of CRISPR into the brain rescues a mouse model of fragile X syndrome from exaggerated repetitive behaviours

Recent advances in biomimetic nanodelivery systems for the treatment of depression

Depression and cognitive disorders remain major challenges in healthcare, with conventional treatments often facing limitations such as slow onset, side effects, and poor drug delivery to the brain. Biomimetic nanodelivery systems, including nanozymes, cell membrane-based systems, and exosomes, have emerged as promising solutions to these issues. These systems leverage natural biological processes to enhance drug targeting, improve bioavailability, and regulate complex biological pathways. Nanoenzymes, with their catalytic properties, offer antioxidant and anti-inflammatory benefits, while cell membranes and exosomes provide efficient targeting and immune evasion. However, challenges remain, including the immaturity of large-scale production techniques, stability concerns, and incomplete understanding of their mechanisms of action. Moreover, the long-term safety, pharmacokinetics, and toxicity of these systems require further investigation. Despite these obstacles, the potential of biomimetic nanodelivery systems to revolutionize depression treatment is significant. Future research should focus on optimizing their preparation, improving drug targeting and release, and ensuring clinical safety. Multidisciplinary collaboration will be essential for advancing these systems from the laboratory to clinical practice, offering new therapeutic avenues for depression and other neurological disorders.

In Vivo Cytosolic Delivery of Biomolecules into Neurons for Super-Resolution Imaging and Genome Modification

Efficient delivery of biomolecules into neurons has significant impacts on therapeutic applications in the central nervous system (CNS) and fundamental neuroscience research. Existing viral and non-viral delivery methods often suffer from inefficient intracellular access due to the endocytic pathway. Here, a neuron-targeting and direct cytosolic delivery platform is discovered by using a 15-amino-acid peptide, termed the N1 peptide, which enables neuron-specific targeting and cytosolic delivery of functional biomolecules. The N1 peptide initially binds hyaluronan in the extracellular matrix and subsequently passes the membrane of neurons without being trapped into endosome. This mechanism facilitates the efficient delivery of cell-impermeable and photo-stable fluorescent dye for super-resolution imaging of dendritic spines, and functional proteins, such as Cre recombinase, for site-specific genome modification. Importantly, the N1 peptide exhibits robust neuronal specificity across diverse species, including mice, rats, tree shrews, and zebra finches. Its targeting capability is further demonstrated through various administration routes, including intraparenchymal, intrathecal, and intravenous (i.v.) injections after blood-brain barrier (BBB) opening with focused ultrasound (FUS). These findings establish the N1 peptide as a versatile and functional platform with significant potential for bioimaging and advanced therapeutic applications.

Lipid Nanoparticles for In Vivo Lung Delivery of CRISPR-Cas9 Ribonucleoproteins Allow Gene Editing of Clinical Targets

In the past 10 years, CRISPR-Cas9 has revolutionized the gene-editing field due to its modularity, simplicity, and efficacy. It has been applied for the creation of in vivo models, to further understand human biology, and toward the curing of genetic diseases. However, there remain significant delivery barriers for CRISPR-Cas9 application in the clinic, especially for in vivo and extrahepatic applications. In this work, high-throughput molecular barcoding techniques were used alongside traditional screening methodologies to simultaneously evaluate LNP formulations encapsulating ribonucleoproteins (RNPs) for in vitro gene-editing efficiency and in vivo biodistribution. This resulted in the identification of a lung-tropic LNP formulation, which shows efficient gene editing in endothelial and epithelial cells within the lung, targeting both model reporter and clinically relevant genomic targets. Further, this LNP shows no off-target indel formation in the liver, making it a highly specific extrahepatic delivery system for lung-editing applications.

Prime Editing: A Revolutionary Technology for Precise Treatment of Genetic Disorders

Genetic diseases have long posed significant challenges, with limited breakthroughs in treatment. Recent advances in gene editing technologies offer new possibilities in gene therapy for the treatment of inherited disorders. However, traditional gene editing methods have limitations that hinder their potential for clinical use, such as limited editing capabilities and the production of unintended byproducts. To overcome these limitations, prime editing (PE) has been developed as a powerful tool for precise and efficient genome modification. In this review, we provide an overview of the latest advancements in PE and its potential applications in the treatment of inherited disorders. Furthermore, we examine the current delivery vehicles employed for delivering PE systems in vitro and in vivo, and analyze their respective benefits and limitations. Ultimately, we discuss the challenges that need to be addressed to fully unlock the potential of PE for the remission or cure of genetic diseases.

Customizable virus-like particles deliver CRISPR-Cas9 ribonucleoprotein for effective ocular neovascular and Huntington's disease gene therapy

In vivo CRISPR gene editing holds enormous potential for various diseases. Ideally, CRISPR delivery should be cell type-specific and time-restricted for optimal efficacy and safety, but customizable methods are lacking. Here we develop a cell-tropism programmable CRISPR-Cas9 ribonucleoprotein delivery system (RIDE) based on virus-like particles. The efficiency of RIDE was comparable to that of adeno-associated virus and lentiviral vectors and higher than lipid nanoparticles. RIDE could be readily reprogrammed to target dendritic cells, T cells and neurons, and significantly ameliorated the disease symptoms in both ocular neovascular and Huntington's disease models via cell-specific gene editing. In addition, RIDE could efficiently edit the huntingtin gene in patients' induced pluripotent stem cell-derived neurons and was tolerated in non-human primates. This study is expected to facilitate the development of in vivo CRISPR therapeutics.

CRISPR-Cas9 Targeting PCSK9: A Promising Therapeutic Approach for Atherosclerosis

CRISPR-Cas9 gene editing technology, as an innovative biomedical tool, holds significant potential in the prevention and treatment of atherosclerosis. By precisely editing key genes such as PCSK9, CRISPR-Cas9 offers the possibility of long-term regulation of low-density lipoprotein cholesterol (LDL-C), which may reduce the risk of cardiovascular diseases. Early clinical studies of gene editing therapies like VERVE-101 have yielded encouraging results, highlighting both the feasibility and potential efficacy of this technology. However, clinical applications still face challenges such as off-target effects, immunogenicity, and long-term safety. Future research should focus on enhancing the specificity and efficiency of gene editing, optimizing delivery systems, and improving personalized treatment strategies. Additionally, the establishment of ethical and legal regulatory frameworks will be critical for the safe adoption of this technology. With the continued advancement of gene editing technology, CRISPR-Cas9 may become an important tool for treating atherosclerosis and other complex diseases.

Advanced delivery systems for gene editing: A comprehensive review from the GenE-HumDi COST Action Working Group

In the past decade, precise targeting through genome editing has emerged as a promising alternative to traditional therapeutic approaches. Genome editing can be performed using various platforms, where programmable DNA nucleases create permanent genetic changes at specific genomic locations due to their ability to recognize precise DNA sequences. Clinical application of this technology requires the delivery of the editing reagents to transplantable cells ex vivo or to tissues and organs for in vivo approaches, often representing a barrier to achieving the desired editing efficiency and safety. In this review, authored by members of the GenE-HumDi European Cooperation in Science and Technology (COST) Action, we described the plethora of delivery systems available for genome-editing components, including viral and non-viral systems, highlighting their advantages, limitations, and potential application in a clinical setting.

Lipid nanoparticle-mediated intracameral mRNA delivery facilitates gene expression and editing in the anterior chamber of the eye

Lipid nanoparticles (LNPs) have shown great potential in the field of gene therapy for retinal diseases. To expand on this application, we investigated LNP-mediated mRNA delivery to the anterior chamber of the eye via the intracameral (IC) route of administration. Here, we show that IC injections of LNPs facilitated protein expression and gene editing in the trabecular meshwork (TM). Administration of Cre-mRNA LNPs to Ai9 mice resulted in robust tdTomato expression in the angle and corneal endothelium. In C57BL/6 mice, mCherry-mRNA LNPs demonstrated localized protein expression in the TM, which peaked at 72 h and subsequently declined over 120 h. Additionally, LNPs encapsulating Cas9 mRNA with sgAi9 enabled in vivo gene editing in Ai9 mice, with up to 14.3 % editing efficiency. This induced tdTomato expression in the iridocorneal angle, validating the potential of LNPs for gene editing applications. Importantly, no ocular toxicity was observed, indicating the safety of the IC LNP administration. Our findings highlight the use of LNPs for targeted gene therapy and editing, paving the path for the treatment of diseases such as glaucoma in the anterior eye.

Non-Invasive Delivery of CRISPR/Cas9 Ribonucleoproteins (Cas9 RNPs) into Cells via Nanoparticles for Membrane Transport

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system is a promising biotechnology tool for genome editing. However, in living organisms, several pharmacokinetic challenges arise, including off-target side effects due to incorrect distribution, low bioavailability caused by membrane impermeability, and instability resulting from enzymatic degradation. Therefore, innovative delivery strategies must be developed to address these issues. Modified nanoparticles offer a potential solution for the non-invasive delivery of CRISPR/Cas9 ribonucleoproteins (Cas9 RNPs). Cas9 RNPs encapsulated in nanoparticles are protected from enzymatic degradation, similar to how microRNAs are shielded within exosomes. It is well-established that certain materials, including proteins, are expressed selectively in specific cell types. For example, the α-7 nicotinic receptor is expressed in endothelial and neuronal cells, while the αvβ3 integrin is expressed in cancer cells. These endogenous materials can facilitate receptor-mediated endocytosis or transcytosis. Nanoparticles encapsulating Cas9 RNPs and coated with ligands targeting such receptors may be internalized through receptor-mediated mechanisms. Once internalized, Cas9 RNPs could perform the desired gene editing in the nucleus after escaping the endosome through mechanisms such as the proton sponge effect or membrane fusion. In this review, I discuss the potential and advantages of delivering Cas9 RNP-encapsulated nanoparticles coated with ligands through receptor-mediated endocytosis or transcytosis.

Advancing CNS Therapeutics: Enhancing Neurological Disorders with Nanoparticle-Based Gene and Enzyme Replacement Therapies

Given the complexity of the central nervous system (CNS) and the diversity of neurological conditions, the increasing prevalence of neurological disorders poses a significant challenge to modern medicine. These disorders, ranging from neurodegenerative diseases to psychiatric conditions, not only impact individuals but also place a substantial burden on healthcare systems and society. A major obstacle in treating these conditions is the blood-brain barrier (BBB), which restricts the passage of therapeutic agents to the brain. Nanotechnology, particularly the use of nanoparticles (NPs), offers a promising solution to this challenge. NPs possess unique properties such as small size, large surface area, and modifiable surface characteristics, enabling them to cross the BBB and deliver drugs directly to the affected brain regions. This review focuses on the application of NPs in gene therapy and enzyme replacement therapy (ERT) for neurological disorders. Gene therapy involves altering or manipulating gene expression and can be enhanced by NPs designed to carry various genetic materials. Similarly, NPs can improve the efficacy of ERT for lysosomal storage disorders (LSDs) by facilitating enzyme delivery to the brain, overcoming issues like immunogenicity and instability. Taken together, this review explores the potential of NPs in revolutionizing treatment options for neurological disorders, highlighting their advantages and the future directions in this rapidly evolving field.

CRISPR-Cas9 Gene Therapy: Non-Viral Delivery and Stimuli-Responsive Nanoformulations

The CRISPR-Cas9 technology, one of the groundbreaking genome editing methods for addressing genetic disorders, has emerged as a powerful, precise, and efficient tool. However, its clinical translation remains hindered by challenges in delivery efficiency and targeting specificity. This review provides a comprehensive analysis of the structural features, advantages, and potential applications of various non-viral and stimuli-responsive systems, examining recent progress to emphasize the potential to address these limitations and advance CRISPR-Cas9 therapeutics. We describe how recent reports emphasize that nonviral vectors, including lipid-based nanoparticles, extracellular vesicles, polymeric nanoparticles, gold nanoparticles, and mesoporous silica nanoparticles, can offer diverse advantages to enhance stability, cellular uptake, and biocompatibility, based on their structures and physio-chemical stability. We also summarize recent progress on stimuli-responsive nanoformulations, a type of non-viral vector, to introduce precision and control in CRISPR-Cas9 delivery. Stimuli-responsive nanoformulations are designed to respond to pH, redox states, and external triggers, facilitate controlled and targeted delivery, and minimize off-target effects. The insights in our review suggest future challenges for clinical applications of gene therapy technologies and highlight the potential of delivery systems to enhance CRISPR-Cas9's clinical efficacy, positioning them as pivotal tools for future gene-editing therapies.

Improving the use of CRISPR/Cas9 gene editing machinery as a cancer therapeutic tool with the help of nanomedicine

CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats-associated protein 9) has revolutionized gene editing tools and paved the way for innovations in medical research for disease diagnosis and treatment. However, better specificity and efficient delivery of this gene machinery make it challenging to successfully edit genes for treating various diseases. This is mainly due to cellular barriers, instability in biological environments, and various off-target effects that prohibit safe and efficient delivery under in vivo conditions. This review examines several delivery modes [plasmid, mRNA, RNP (ribonucleoprotein)] and methods for the CRISPR-Cas9 system delivery, focusing on its potential applications in cancer therapy. Biocompatibility and cytotoxicity are crucial factors determining their safe and effective use. Various nanomaterials have been reviewed for their biocompatibility, limitations, and challenges in treating cancer. Among the reviewed nanoparticles, lipid nanoparticles (LNPs) stand out for their biocompatibility due to their biomimetic lipid bilayer that effectively delivers CRISPR/Cas9 cargoes while reducing toxicity. We discuss challenges in in vivo delivery and associated findings such as encapsulation, target delivery, controlled release, and endosomal escape. Future directions involve addressing limitations and adapting CRISPR-Cas9 for clinical trials, ensuring its safe and effective use.

Drug delivery using gold nanoparticles

Modern nanotechnologies provide various possibilities for efficiently delivering drugs to biological targets. This review focuses on using functionalized gold nanoparticles (GNPs) as a drug delivery platform. Owing to their exceptional size and surface characteristics, GNPs are a perfect drug delivery vehicle for targeted and selective distribution. Several in vitro and in vivo tests have shown how simple it is to tailor these particles to administer chemical medications straight to tumors. The GNP surface can also be coated with ligands to modify drug release or improve selectivity. Moreover, the pharmacological activity can be enhanced by using the photothermal characteristics of the particles.

Nanomaterials for intelligent CRISPR-Cas tools: improving environment sustainability

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) is a desirable gene modification tool covering a wide area in various sectors of medicine, agriculture, and microbial biotechnology. The role of this incredible genetic engineering technology has been extensively investigated; however, it remains formidable with cargo choices, nonspecific delivery, and insertional mutagenesis. Various nanomaterials including lipid, polymeric, and inorganic are being used to deliver the CRISPR-Cas system. Progress in nanomaterials could potentially address these challenges by accelerating precision targeting, cost-effectiveness, and one-step delivery. In this review, we highlighted the advances in nanotechnology and nanomaterials as smart delivery systems for CRISPR-Cas so as to ameliorate applications for environmental remediation including biomedical research and healthcare, strategies for mitigating antimicrobial resistance, and to be used as nanofertilizers for enhancing crop growth, and reducing the environmental impact of traditional fertilizers. The timely co-evolution of nanotechnology and CRISPR technologies has contributed to smart novel nanostructure hybrids for improving the onerous tasks of environmental remediation and biological sustainability.

Nanotechnology in Pain Management

Chronic pain is a debilitating condition that affects millions of patients worldwide, contributing to a high disease burden and millions of dollars in lost wages, missed workdays, and healthcare costs. Opioids, NSAIDs, acetaminophen, gabapentinoids, muscle relaxants, anticonvulsants, and antidepressants are the most used medications for chronic pain and carry significant side effects, including gastric bleeding, hepatotoxicity, stroke, kidney damage, constipation, dizziness, and arrhythmias. Opioids in particular carry the risk of long-term dependence, drug tolerance, and overdose. In 2022, 81,806 people died from opioid overdose in the United States alone. Alternative treatments for chronic pain are critically needed, and nanotechnology has emerged as a promising means of achieving effective long-term analgesia while avoiding the adverse side effects associated with conventional pharmacological agents. Nanotechnology-based treatments include liposomes, Poly Lactic-co-Glycolic Acid (PLGA) and other polymeric nanoparticles, and carbon-based polymers, which can help mitigate those adverse side effects. These nanomaterials can serve as drug delivery systems that facilitate controlled release and drug stability via the encapsulation of free molecules and protein-based drugs, leading to longer-lasting analgesia and minimizing side effects. In this review, we examine the role of nanotechnology in addressing concerns associated with conventional chronic pain treatments and discuss the ongoing efforts to develop novel, nanotechnology-based treatments for chronic pain such as nanocapacitor patches, gene therapy, the use of both viral and non-viral vectors, CRISPR, and scavengers.

Widespread Gene Editing in the Brain via In Utero Delivery of mRNA Using Acid-Degradable Lipid Nanoparticles

In utero gene editing with mRNA-based therapeutics has the potential to revolutionize the treatment of neurodevelopmental disorders. However, a critical bottleneck in clinical application has been the lack of mRNA delivery vehicles that can efficiently transfect cells in the brain. In this report, we demonstrate that in utero intracerebroventricular (ICV) injection of densely PEGylated lipid nanoparticles (ADP-LNPs) containing an acid-degradable PEG-lipid can safely and effectively deliver mRNA for gene editing enzymes to the fetal mouse brain, resulting in successful transfection and editing of brain cells. ADP-LNPs containing Cre mRNA transfected 30% of the fetal brain cells in Ai9 mice and had no detectable adverse effects on fetal development and postnatal growth. In addition, ADP-LNPs efficiently transfected neural stem and progenitor cells in Ai9 mice with Cre mRNA, which subsequently proliferated and caused over 40% of the cortical neurons and 60% of the hippocampal neurons to be edited in treated mice 10 weeks after birth. Furthermore, using Angelman syndrome, a paradigmatic neurodevelopmental disorder, as a disease model, we demonstrate that ADP-LNPs carrying Cas9 mRNA and gRNA induced indels in 21% of brain cells within 7 days postpartum, underscoring the precision and potential of this approach. These findings demonstrate that LNP/mRNA complexes have the potential to be a transformative tool for in utero treatment of neurodevelopmental disorders and set the stage for a frontier in treating neurodevelopmental disorders that focuses on curing genetic diseases before birth.

Lung and liver editing by lipid nanoparticle delivery of a stable CRISPR-Cas9 ribonucleoprotein

Lipid nanoparticle (LNP) delivery of clustered regularly interspaced short palindromic repeat (CRISPR) ribonucleoproteins (RNPs) could enable high-efficiency, low-toxicity and scalable in vivo genome editing if efficacious RNP-LNP complexes can be reliably produced. Here we engineer a thermostable Cas9 from Geobacillus stearothermophilus (GeoCas9) to generate iGeoCas9 variants capable of >100× more genome editing of cells and organs compared with the native GeoCas9 enzyme. Furthermore, iGeoCas9 RNP-LNP complexes edit a variety of cell types and induce homology-directed repair in cells receiving codelivered single-stranded DNA templates. Using tissue-selective LNP formulations, we observe genome-editing levels of 16‒37% in the liver and lungs of reporter mice that receive single intravenous injections of iGeoCas9 RNP-LNPs. In addition, iGeoCas9 RNPs complexed to biodegradable LNPs edit the disease-causing SFTPC gene in lung tissue with 19% average efficiency, representing a major improvement over genome-editing levels observed previously using viral or nonviral delivery strategies. These results show that thermostable Cas9 RNP-LNP complexes can expand the therapeutic potential of genome editing.

Advances in Nanoparticles as Non-Viral Vectors for Efficient Delivery of CRISPR/Cas9

The clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system is a gene-editing technology. Nanoparticle delivery systems have attracted attention because of the limitations of conventional viral vectors. In this review, we assess the efficiency of various nanoparticles, including lipid-based, polymer-based, inorganic, and extracellular vesicle-based systems, as non-viral vectors for CRISPR/Cas9 delivery. We discuss their advantages, limitations, and current challenges. By summarizing recent advancements and highlighting key strategies, this review aims to provide a comprehensive overview of the role of non-viral delivery systems in advancing CRISPR/Cas9 technology for clinical applications and gene therapy.

Precision epigenetic editing: Technological advances, enduring challenges, and therapeutic applications

The epigenome is a complex framework through which gene expression is precisely and flexibly modulated to incorporate heritable memory and responses to environmental stimuli. It governs diverse cellular processes, including cell fate, disease, and aging. The need to understand this system and precisely control gene expression outputs for therapeutic purposes has precipitated the development of a diverse set of epigenetic editing tools. Here, we review the existing toolbox for targeted epigenetic editing, technical considerations of the current technologies, and opportunities for future development. We describe applications of therapeutic epigenetic editing and their potential for treating disease, with a discussion of ongoing delivery challenges that impede certain clinical interventions, particularly in the brain. With simultaneous advancements in available engineering tools and appropriate delivery technologies, we predict that epigenetic editing will increasingly cement itself as a powerful approach for safely treating a wide range of disorders in all tissues of the body.

Delivery of nucleic acid based genome editing platforms via lipid nanoparticles: Clinical applications

CRISPR/Cas technology presents a promising approach for treating a wide range of diseases, including cancer and genetic disorders. Despite its potential, the translation of CRISPR/Cas into effective in-vivo gene therapy encounters challenges, primarily due to the need for safe and efficient delivery mechanisms. Lipid nanoparticles (LNPs), FDA-approved for RNA delivery, show potential for delivering also CRISPR/Cas, offering the capability to efficiently encapsulate large mRNA molecules with single guide RNAs. However, achieving precise targeting in-vivo remains a significant obstacle, necessitating further research into optimizing LNP formulations. Strategies to enhance specificity, such as modifying LNP structures and incorporating targeting ligands, are explored to improve organ and cell type targeting. Furthermore, the development of base and prime editing technology presents a potential breakthrough, offering precise modifications without generating double-strand breaks (DSBs). Prime editing, particularly when delivered via targeted LNPs, holds promise for treating diverse diseases safely and precisely. This review assesses both the progress made and the persistent challenges faced in using LNP-encapsulated CRISPR-based technologies for therapeutic purposes, with a particular focus on clinical translation.

CRISPR technology in human diseases

Gene editing is a growing gene engineering technique that allows accurate editing of a broad spectrum of gene-regulated diseases to achieve curative treatment and also has the potential to be used as an adjunct to the conventional treatment of diseases. Gene editing technology, mainly based on clustered regularly interspaced palindromic repeats (CRISPR)-CRISPR-associated protein systems, which is capable of generating genetic modifications in somatic cells, provides a promising new strategy for gene therapy for a wide range of human diseases. Currently, gene editing technology shows great application prospects in a variety of human diseases, not only in therapeutic potential but also in the construction of animal models of human diseases. This paper describes the application of gene editing technology in hematological diseases, solid tumors, immune disorders, ophthalmological diseases, and metabolic diseases; focuses on the therapeutic strategies of gene editing technology in sickle cell disease; provides an overview of the role of gene editing technology in the construction of animal models of human diseases; and discusses the limitations of gene editing technology in the treatment of diseases, which is intended to provide an important reference for the applications of gene editing technology in the human disease.

CRISPR-Cpf1 system and its applications in animal genome editing

The clustered regularly interspaced short palindromic repeats (CRISPR) and their associated protein (Cas) system is a gene editing technology guided by RNA endonuclease. The CRISPR-Cas12a (also known as CRISPR-Cpf1) system is extensively utilized in genome editing research due to its accuracy and high efficiency. In this paper, we primarily focus on the application of CRISPR-Cpf1 technology in the construction of disease models and gene therapy. Firstly, the structure and mechanism of the CRISPR-Cas system are introduced. Secondly, the similarities and differences between CRISPR-Cpf1 and CRISPR-Cas9 technologies are compared. Thirdly, the main focus is on the application of the CRISPR-Cpf1 system in cell and animal genome editing. Finally, the challenges faced by CRISPR-Cpf1 technology and corresponding strategies are analyzed. Although CRISPR-Cpf1 technology has certain off-target effects, it can effectively and accurately edit cell and animal genomes, and has significant advantages in the preclinical research.

Electrokinetic convection-enhanced delivery for infusion into the brain from a hydrogel reservoir

Electrokinetic convection-enhanced delivery (ECED) utilizes an external electric field to drive the delivery of molecules and bioactive substances to local regions of the brain through electroosmosis and electrophoresis, without the need for an applied pressure. We characterize the implementation of ECED to direct a neutrally charged fluorophore (3 kDa) from a doped biocompatible acrylic acid/acrylamide hydrogel placed on the cortical surface. We compare fluorophore infusion profiles using ECED (time = 30 min, current = 50 µA) and diffusion-only control trials, for ex vivo (N = 18) and in vivo (N = 12) experiments. The linear intensity profile of infusion to the brain is significantly higher in ECED compared to control trials, both for in vivo and ex vivo. The linear distance of infusion, area of infusion, and the displacement of peak fluorescence intensity along the direction of infusion in ECED trials compared to control trials are significantly larger for in vivo trials, but not for ex vivo trials. These results demonstrate the effectiveness of ECED to direct a solute from a surface hydrogel towards inside the brain parenchyma based predominantly on the electroosmotic vector.

Nanoplatform-Based In Vivo Gene Delivery Systems for Cancer Therapy

Gene therapy uses modern molecular biology methods to repair disease-causing genes. As a burgeoning therapeutic, it has been widely applied for cancer therapy. Since 1989, there have been numerous clinical gene therapy cases worldwide. However, a few are successful. The main challenge of clinical gene therapy is the lack of efficient and safe vectors. Although viral vectors show high transfection efficiency, their application is still limited by immune rejection and packaging capacity. Therefore, the development of non-viral vectors is overwhelming. Nanoplatform-based non-viral vectors become a hotspot in gene therapy. The reasons are mainly as follows. 1) Non-viral vectors can be engineered to be uptaken by specific types of cells or tissues, providing effective targeting capability. 2) Non-viral vectors can protect goods that need to be delivered from degradation. 3) Nanoparticles can transport large-sized cargo such as CRISPR/Cas9 plasmids and nucleoprotein complexes. 4) Nanoparticles are highly biosafe, and they are not mutagenic in themselves compared to viral vectors. 5) Nanoparticles are easy to scale preparation, which is conducive to clinical conversion and application. Here, an overview of the categories of nanoplatform-based non-viral gene vectors, the limitations on their development, and their applications in cancer therapy.

Peptide-encoding gene transfer to modulate intracellular protein-protein interactions

Peptide drug discovery has great potential, but the cell membrane is a major obstacle when the target is an intracellular protein-protein interaction (PPI). It is difficult to target PPIs with small molecules; indeed, there are no intervention tools that can target any intracellular PPI. In this study, we developed a platform that enables the introduction of peptides into cells via mRNA-based gene delivery. Peptide-length nucleic acids do not enable stable ribosome binding and exhibit little to no translation into protein. In this study, a construct was created in which the sequence encoding dihydrofolate reductase (DHFR) was placed in front of the sequence encoding the target peptide, together with a translation skipping sequence, as a sequence that meets the requirements of promoting ribosome binding and rapid decay of the translated protein. This enabled efficient translation from the mRNA encoding the target protein while preventing unnecessary protein residues. Using this construct, we showed that it can inhibit Drp1/Fis1 binding, one of the intracellular PPIs, which governs mitochondrial fission, an important aspect of mitochondrial dynamics. In addition, it was shown to inhibit pathological hyperfission, normalize mitochondrial dynamics and metabolism, and inhibit apoptosis of the mitochondrial pathway.

Emerging Perspectives on Prime Editor Delivery to the Brain

Prime editing shows potential as a precision genome editing technology, as well as the potential to advance the development of next-generation nanomedicine for addressing neurological disorders. However, turning in prime editors (PEs), which are macromolecular complexes composed of CRISPR/Cas9 nickase fused with a reverse transcriptase and a prime editing guide RNA (pegRNA), to the brain remains a considerable challenge due to physiological obstacles, including the blood-brain barrier (BBB). This review article offers an up-to-date overview and perspective on the latest technologies and strategies for the precision delivery of PEs to the brain and passage through blood barriers. Furthermore, it delves into the scientific significance and possible therapeutic applications of prime editing in conditions related to neurological diseases. It is targeted at clinicians and clinical researchers working on advancing precision nanomedicine for neuropathologies.

Near-Infrared Light Activated Formulation for the Spatially Controlled Release of CRISPR-Cas9 Ribonucleoprotein for Brain Gene Editing

The CRISPR/Cas9 system has emerged as a promising platform for gene editing; however, the lack of an efficient and safe delivery system to introduce it into cells continues to hinder clinical translation. Here, we report a rationally designed gene-editing nanoparticle (NP) formulation for brain applications: an sgRNA:Cas9 ribonucleoprotein complex is immobilized on the NP surface by oligonucleotides that are complementary to the sgRNA. Irradiation of the formulation with a near-infrared (NIR) laser generates heat in the NP, leading to the release of the ribonucleoprotein complex. The gene-editing potential of the formulation was demonstrated in vitro at the single-cell level. The safety and gene editing of the formulation were also demonstrated in the brains of reporter mice, specifically in the subventricular zone after intracerebral administration and in the olfactory bulb after intranasal administration. The formulation presented here offers a new strategy for the spatially controlled delivery of the CRISPR system to the brain.

Delivering CRISPR to the HIV-1 reservoirs

Human immunodeficiency virus type 1 (HIV-1) infection is well known as one of the most complex and difficult viral infections to cure. The difficulty in developing curative strategies arises in large part from the development of latent viral reservoirs (LVRs) within anatomical and cellular compartments of a host. The clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9 (CRISPR/Cas9) system shows remarkable potential for the inactivation and/or elimination of integrated proviral DNA within host cells, however, delivery of the CRISPR/Cas9 system to infected cells is still a challenge. In this review, the main factors impacting delivery, the challenges for delivery to each of the LVRs, and the current successes for delivery to each reservoir will be discussed.

Blood-Brain Barrier-Targeting Nanoparticles: Biomaterial Properties and Biomedical Applications in Translational Neuroscience

Overcoming the blood-brain barrier (BBB) remains a significant hurdle in effective drug delivery to the brain. While the BBB serves as a crucial protective barrier, it poses challenges in delivering therapeutic agents to their intended targets within the brain parenchyma. To enhance drug delivery for the treatment of neurological diseases, several delivery technologies to circumvent the BBB have been developed in the last few years. Among them, nanoparticles (NPs) are one of the most versatile and promising tools. Here, we summarize the characteristics of NPs that facilitate BBB penetration, including their size, shape, chemical composition, surface charge, and importantly, their conjugation with various biological or synthetic molecules such as glucose, transferrin, insulin, polyethylene glycol, peptides, and aptamers. Additionally, we discuss the coating of NPs with surfactants. A comprehensive overview of the common in vitro and in vivo models of the BBB for NP penetration studies is also provided. The discussion extends to discussing BBB impairment under pathological conditions and leveraging BBB alterations under pathological conditions to enhance drug delivery. Emphasizing the need for future studies to uncover the inherent therapeutic properties of NPs, the review advocates for their role beyond delivery systems and calls for efforts translating NPs to the clinic as therapeutics. Overall, NPs stand out as a highly promising therapeutic strategy for precise BBB targeting and drug delivery in neurological disorders.

Evolving Tumor Characteristics and Smart Nanodrugs for Tumor Immunotherapy

Typical physiological characteristics of tumors, such as weak acidity, low oxygen content, and upregulation of certain enzymes in the tumor microenvironment (TME), provide survival advantages when exposed to targeted attacks by drugs and responsive nanomedicines. Consequently, cancer treatment has significantly progressed in recent years. However, the evolution and adaptation of tumor characteristics still pose many challenges for current treatment methods. Therefore, efficient and precise cancer treatments require an understanding of the heterogeneity degree of various factors in cancer cells during tumor evolution to exploit the typical TME characteristics and manage the mutation process. The highly heterogeneous tumor and infiltrating stromal cells, immune cells, and extracellular components collectively form a unique TME, which plays a crucial role in tumor malignancy, including proliferation, invasion, metastasis, and immune escape. Therefore, the development of new treatment methods that can adapt to the evolutionary characteristics of tumors has become an intense focus in current cancer treatment research. This paper explores the latest understanding of cancer evolution, focusing on how tumors use new antigens to shape their "new faces"; how immune system cells, such as cytotoxic T cells, regulatory T cells, macrophages, and natural killer cells, help tumors become "invisible", that is, immune escape; whether the diverse cancer-associated fibroblasts provide support and coordination for tumors; and whether it is possible to attack tumors in reverse. This paper discusses the limitations of targeted therapy driven by tumor evolution factors and explores future strategies and the potential of intelligent nanomedicines, including the systematic coordination of tumor evolution factors and adaptive methods, to meet this therapeutic challenge.

Dual-responsive nanocarriers for efficient cytosolic protein delivery and CRISPR-Cas9 gene therapy of inflammatory skin disorders

Developing protein drugs that can target intracellular sites remains a challenge due to their inadequate membrane permeability. Efficient carriers for cytosolic protein delivery are required for protein-based drugs, cancer vaccines, and CRISPR-Cas9 gene therapies. Here, we report a screening process to identify highly efficient materials for cytosolic protein delivery from a library of dual-functionalized polymers bearing both boronate and lipoic acid moieties. Both ligands were found to be crucial for protein binding, endosomal escape, and intracellular protein release. Polymers with higher grafting ratios exhibit remarkable efficacies in cytosolic protein delivery including enzymes, monoclonal antibodies, and Cas9 ribonucleoprotein while preserving their activity. Optimal polymer successfully delivered Cas9 ribonucleoprotein targeting NLRP3 to disrupt NLRP3 inflammasomes in vivo and ameliorate inflammation in a mouse model of psoriasis. Our study presents a promising option for the discovery of highly efficient materials tailored for cytosolic delivery of specific proteins and complexes such as Cas9 ribonucleoprotein.

Non-viral systems for intracellular delivery of genome editing tools

A hallmark of the last decades is an extensive development of genome editing systems and technologies propelling genetic engineering to the next level. Specific and efficient delivery of genome editing tools to target cells is one of the key elements of such technologies. Conventional vectors are not always suitable for this purpose due to a limited cargo volume, risks related to cancer and immune reactions, toxicity, a need for high-purity viral material and quality control, as well as a possibility of integration of the virus into the host genome leading to overexpression of the vector components and safety problems. Therefore, the search for novel approaches to delivering proteins and nucleic acids into cells is a relevant priority. This work reviews abiotic vectors and systems for delivering genome editing tools into target cells, including liposomes and solid lipid particles, other membrane-based vesicles, cell-penetrating peptides, micelles, dendrimers, carbon nanotubes, inorganic, polymer, metal and other nanoparticles. It considers advantages, drawbacks and preferred applications of such systems as well as suitability thereof for the delivery of genome editing systems. A particular emphasis is placed on metal-organic frameworks (MOFs) and their potential in the targeted intracellular delivery of proteins and polynucleotides. It has been concluded that further development of MOF-based vectors and technologies, as well as combining MOFs with other carriers can result in safe and efficient delivery systems, which would be able to circulate in the body for a long time while recognizing target cells and ensuring cell-specific delivery and release of intact cargoes and, thereby, improving the genome editing outcome.

CRISPR-Based Gene Editing Techniques in Pediatric Neurological Disorders

The emergence of gene editing technologies offers a unique opportunity to develop mutation-specific treatments for pediatric neurological disorders. Gene editing systems can potentially alter disease trajectory by correcting dysfunctional mutations or therapeutically altering gene expression. Clustered regularly interspaced short palindromic repeats (CRISPR)-based approaches are attractive gene therapy platforms to personalize treatments because of their specificity, ease of design, versatility, and cost. However, many such approaches remain in the early stages of development, with ongoing efforts to optimize editing efficiency, minimize unintended off-target effects, and mitigate pathologic immune responses. Given the rapid evolution of CRISPR-based therapies, it is prudent for the clinically based child neurologist to have a conceptual understanding of what such therapies may entail, including both benefits and risks and how such therapies may be clinically applied. In this review, we describe the fundamentals of CRISPR-based therapies, discuss the opportunities and challenges that have arisen, and highlight preclinical work in several pediatric neurological diseases.

Techniques for investigating lncRNA transcript functions in neurodevelopment

Long noncoding RNAs (lncRNAs) are sequences of 200 nucleotides or more that are transcribed from a large portion of the mammalian genome. While hypothesized to have a variety of biological roles, many lncRNAs remain largely functionally uncharacterized due to unique challenges associated with their investigation. For example, some lncRNAs overlap with other genomic loci, are expressed in a cell-type-specific manner, and/or are differentially processed at the post-transcriptional level. The mammalian CNS contains a vast diversity of lncRNAs, and lncRNAs are highly abundant in the mammalian brain. However, interrogating lncRNA function in models of the CNS, particularly in vivo, can be complex and challenging. Here we review the breadth of methods used to investigate lncRNAs in the CNS, their merits, and the understanding they can provide with respect to neurodevelopment and pathophysiology. We discuss remaining challenges in the field and provide recommendations to assay lncRNAs based on current methods.

CRISPR/Cas systems combined with DNA nanostructures for biomedical applications

DNA nanostructures are easy to design and construct, have good biocompatibility, and show great potential in biosensing and drug delivery. Numerous distinctive and versatile DNA nanostructures have been developed and explored for biomedical applications. In addition to DNA nanostructures that are completely assembled from DNA, composite DNA nanostructures obtained by combining DNA with other organic or inorganic materials are also widely used in related research. The CRISPR/Cas system has attracted great attention as a powerful gene editing technology and is also widely used in biomedical diagnosis. Many researchers are committed to exploring new possibilities by combining DNA nanostructures with CRISPR/Cas systems. These explorations provide support for the development of new detection methods and cargo delivery pathways, provide inspiration for improving relevant gene editing platforms, and further expand the application scope of DNA nanostructures and CRISPR/Cas systems. This paper mainly reviews the design principles and biomedical applications of CRISPR/Cas combined with DNA nanostructures based on the types of DNA nanostructures. Finally, the application status, challenges and development prospects of CRISPR/Cas combined with DNA nanostructures in detection and delivery are summarized. It is expected that this review will enable researchers to better understand the current state of the field and provide insights into the application of CRISPR/Cas systems and the development of DNA nanostructures.

Targeted nonviral delivery of genome editors in vivo

Cell-type-specific in vivo delivery of genome editing molecules is the next breakthrough that will drive biological discovery and transform the field of cell and gene therapy. Here, we discuss recent advances in the delivery of CRISPR-Cas genome editors either as preassembled ribonucleoproteins or encoded in mRNA. Both strategies avoid pitfalls of viral vector-mediated delivery and offer advantages including transient editor lifetime and potentially streamlined manufacturing capability that are already proving valuable for clinical use. We review current applications and future opportunities of these emerging delivery approaches that could make genome editing more efficacious and accessible in the future.

Engineering self-deliverable ribonucleoproteins for genome editing in the brain

The delivery of CRISPR ribonucleoproteins (RNPs) for genome editing in vitro and in vivo has important advantages over other delivery methods, including reduced off-target and immunogenic effects. However, effective delivery of RNPs remains challenging in certain cell types due to low efficiency and cell toxicity. To address these issues, we engineer self-deliverable RNPs that can promote efficient cellular uptake and carry out robust genome editing without the need for helper materials or biomolecules. Screening of cell-penetrating peptides (CPPs) fused to CRISPR-Cas9 protein identifies potent constructs capable of efficient genome editing of neural progenitor cells. Further engineering of these fusion proteins establishes a C-terminal Cas9 fusion with three copies of A22p, a peptide derived from human semaphorin-3a, that exhibits substantially improved editing efficacy compared to other constructs. We find that self-deliverable Cas9 RNPs generate robust genome edits in clinically relevant genes when injected directly into the mouse striatum. Overall, self-deliverable Cas9 proteins provide a facile and effective platform for genome editing in vitro and in vivo.

Hereditary Ataxias: From Bench to Clinic, Where Do We Stand?

Cerebellar ataxias are a wide heterogeneous group of movement disorders. Within this broad umbrella of diseases, there are both genetics and sporadic forms. The clinical presentation of these conditions can exhibit a diverse range of symptoms across different age groups, spanning from pure cerebellar manifestations to sensory ataxia and multisystemic diseases. Over the last few decades, advancements in our understanding of genetics and molecular pathophysiology related to both dominant and recessive ataxias have propelled the field forward, paving the way for innovative therapeutic strategies aimed at preventing and arresting the progression of these diseases. Nevertheless, the rarity of certain forms of ataxia continues to pose challenges, leading to limited insights into the etiology of the disease and the identification of target pathways. Additionally, the lack of suitable models hampers efforts to comprehensively understand the molecular foundations of disease's pathophysiology and test novel therapeutic interventions. In the following review, we describe the epidemiology, symptomatology, and pathological progression of hereditary ataxia, including both the prevalent and less common forms of these diseases. Furthermore, we illustrate the diverse molecular pathways and therapeutic approaches currently undergoing investigation in both pre-clinical studies and clinical trials. Finally, we address the existing and anticipated challenges within this field, encompassing both basic research and clinical endeavors.

Self-delivering, chemically modified CRISPR RNAs for AAV co-delivery and genome editing in vivo

Guide RNAs offer programmability for CRISPR-Cas9 genome editing but also add challenges for delivery. Chemical modification, which has been key to the success of oligonucleotide therapeutics, can enhance the stability, distribution, cellular uptake, and safety of nucleic acids. Previously, we engineered heavily and fully modified SpyCas9 crRNA and tracrRNA, which showed enhanced stability and retained activity when delivered to cultured cells in the form of the ribonucleoprotein complex. In this study, we report that a short, fully stabilized oligonucleotide (a 'protecting oligo'), which can be displaced by tracrRNA annealing, can significantly enhance the potency and stability of a heavily modified crRNA. Furthermore, protecting oligos allow various bioconjugates to be appended, thereby improving cellular uptake and biodistribution of crRNA in vivo. Finally, we achieved in vivo genome editing in adult mouse liver and central nervous system via co-delivery of unformulated, chemically modified crRNAs with protecting oligos and AAV vectors that express tracrRNA and either SpyCas9 or a base editor derivative. Our proof-of-concept establishment of AAV/crRNA co-delivery offers a route towards transient editing activity, target multiplexing, guide redosing, and vector inactivation.

Current Advancement and Future Prospects: Biomedical Nanoengineering

Recent advancements in biomedicine have seen a significant reliance on nanoengineering, as traditional methods often fall short in harnessing the unique attributes of biomaterials. Nanoengineering has emerged as a valuable approach to enhance and enrich the performance and functionalities of biomaterials, driving research and development in the field. This review emphasizes the most prevalent biomaterials used in biomedicine, including polymers, nanocomposites, and metallic materials, and explores the pivotal role of nanoengineering in developing biomedical treatments and processes. Particularly, the review highlights research focused on gaining an in-depth understanding of material properties and effectively enhancing material performance through molecular dynamics simulations, all from a nanoengineering perspective.

Cyclodextrin-based tailored polyrotaxanes for highly efficient delivery of the genome-editing molecule

Direct cytosolic delivery of the Cas9 ribonucleoprotein is the most promising method for inducing CRISPR-Cas9 genome editing in mammalian cells. Recently, we focused the movable properties of cyclodextrin-based polyrotaxanes (PRXs), which consist of numerous cyclodextrins threaded onto the axile molecule with bulky endcaps at both ends of the axile molecule, and developed aminated PRXs as multistep transformable carriers for Cas9 ribonucleoprotein, ensuring efficient complexation, cellular internalization, endosomal escape, release, and nuclear localization. This study reports the structural fine-tuning and structure-property relationship of multistep transformable PRXs for more efficient Cas9 ribonucleoprotein delivery. Among various PRXs, PRX derivatives with a longer molecular length (35 kDa polyethylene glycol as the axile molecule) and a low total degree of substitution (1.5 amino groups/α-cyclodextrins), as well as the modified ratio of two modified amines (cystamine and diethylenetriamine) = ≈1:1, exhibited the highest genome-editing efficacy and intracellular dynamics control. These structural properties are important for efficient endosomal escape and Cas9 RNP release. Furthermore, ligand-modified-β-CD, which can endow the ligand through complexation with PRX termini, improved the cellular uptake and genome-editing effects of the optimized PRX/Cas9 RNP in target cells. Thus, structural fine-tuning and the addition of ligand-modified-β-cyclodextrin enabled efficient genome editing by the Cas9 RNP.

Nanoparticle-mediated delivery of non-viral gene editing technology to the brain

Neurological disorders pose a significant burden on individuals and society, affecting millions worldwide. These disorders, including but not limited to Alzheimer's disease, Parkinson's disease, and Huntington's disease, often have limited treatment options and can lead to progressive degeneration and disability. Gene editing technologies, including Zinc Finger Nucleases (ZFN), Transcription Activator-Like Effector Nucleases (TALEN), and Clustered Regularly Interspaced Short Palindromic Repeats-associated Protein 9 (CRISPR-Cas9), offer a promising avenue for potential cures by targeting and correcting the underlying genetic mutations responsible for neurologic disorders. However, efficient delivery methods are crucial for the successful application of gene editing technologies in the context of neurological disorders. The central nervous system presents unique challenges to treatment development due to the blood-brain barrier, which restricts the entry of large molecules. While viral vectors are traditionally used for gene delivery, nonviral delivery methods, such as nanoparticle-mediated delivery, offer safer alternatives that can efficiently transport gene editing components. Herein we aim to introduce the three main gene editing nucleases as nonviral treatments for neurologic disorders, the delivery barriers associated with brain targeting, and the current nonviral techniques used for brain-specific delivery. We highlight the challenges and opportunities for future research in this exciting and growing field that could lead to blood-brain barrier bypassing therapeutic gene editing.

Lipid Nanoparticles Deliver mRNA to the Brain after an Intracerebral Injection

Neurological disorders are often debilitating conditions with no cure. The majority of current therapies are palliative rather than disease-modifying; therefore, new strategies for treating neurological disorders are greatly needed. mRNA-based therapeutics have great potential for treating such neurological disorders; however, challenges with delivery have limited their clinical potential. Lipid nanoparticles (LNPs) are a promising delivery vector for the brain, given their safer toxicity profile and higher efficacy. Despite this, very little is known about LNP-mediated delivery of mRNA into the brain. Here, we employ MC3-based LNPs and successfully deliver Cre mRNA and Cas9 mRNA/Ai9 sgRNA to the adult Ai9 mouse brain; greater than half of the entire striatum and hippocampus was found to be penetrated along the rostro-caudal axis by direct intracerebral injections of MC3 LNP mRNAs. MC3 LNP Cre mRNA successfully transfected cells in the striatum (∼52% efficiency) and hippocampus (∼49% efficiency). In addition, we demonstrate that MC3 LNP Cas9 mRNA/Ai9 sgRNA edited cells in the striatum (∼7% efficiency) and hippocampus (∼3% efficiency). Further analysis demonstrates that MC3 LNPs mediate mRNA delivery to multiple cell types including neurons, astrocytes, and microglia in the brain. Overall, LNP-based mRNA delivery is effective in brain tissue and shows great promise for treating complex neurological disorders.

Enhancing CRISPR/Cas systems with nanotechnology

CRISPR/Cas systems have revolutionized biology and medicine, and have led to new paradigms in disease diagnostics and therapeutics. However, these complexes suffer from key limitations regarding barriers to cellular entry, stability in biological environments, and off-target effects. Integrating nanotechnology with CRISPR/Cas systems has emerged as a promising strategy to overcome these challenges and has further unlocked structures that accumulate preferentially in tissues of interest, have tunable pharmacological properties, and are activated in response to desired stimuli. Nanomaterials can also enhance CRISPR/Cas-mediated detection platforms by enabling faster, more sensitive, and convenient readouts. We highlight recent advances in this rapidly growing field. We also outline areas that need further development to fully realize the potential of CRISPR technologies.

Control of Selective mRNA Translation in Neuronal Subcellular Compartments in Health and Disease

In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.

Drug delivery systems for CRISPR-based genome editors

CRISPR-based drugs can theoretically manipulate any genetic target. In practice, however, these drugs must enter the desired cell without eliciting an unwanted immune response, so a delivery system is often required. Here, we review drug delivery systems for CRISPR-based genome editors, focusing on adeno-associated viruses and lipid nanoparticles. After describing how these systems are engineered and their subsequent characterization in preclinical animal models, we highlight data from recent clinical trials. Preclinical targeting mediated by polymers, proteins, including virus-like particles, and other vehicles that may deliver CRISPR systems in the future is also discussed.

Recent Advances in CRISPR/Cas9 Delivery Approaches for Therapeutic Gene Editing of Stem Cells

Rapid advancement in genome editing technologies has provided new promises for treating neoplasia, cardiovascular, neurodegenerative, and monogenic disorders. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has emerged as a powerful gene editing tool offering advantages, including high editing efficiency and low cost over the conventional approaches. Human pluripotent stem cells (hPSCs), with their great proliferation and differentiation potential into different cell types, have been exploited in stem cell-based therapy. The potential of hPSCs and the capabilities of CRISPR/Cas9 genome editing has been paradigm-shifting in medical genetics for over two decades. Since hPSCs are categorized as hard-to-transfect cells, there is a critical demand to develop an appropriate and effective approach for CRISPR/Cas9 delivery into these cells. This review focuses on various strategies for CRISPR/Cas9 delivery in stem cells.

CRISPR/Cas9-mediated knock-in of BRCA1/2 mutations restores response to olaparib in pancreatic cancer cell lines

Pancreatic cancer is one of the most aggressive diseases with a very poor outcome. Olaparib, a PARP inhibitor, as maintenance therapy showed benefits in patients with metastatic pancreatic adenocarcinoma bearing germline BRCA1/2 mutations. However, germline BRCA mutation has been described in only 4-7% of patients with pancreatic adenocarcinoma. A CRISPR/Cas9-mediated system was used to knock-in the c.763G > T p.(Glu255*) and c.2133C > A p.(Cys711*) mutations in cell lines to obtain truncated BRCA1 and BRCA2 proteins, respectively. A CRISPR/Cas9 ribonucleoprotein complex was assembled for each mutation and transfected into two pancreatic cell lines (T3M4 and Capan-2) and into a breast cancer cell lines (MCF7) as control. BRCA protein levels were significantly decreased in all BRCA-depleted cells (P < 0.05), proving the transfection efficiency of our CRISPR/Cas9 systems. As expected, the calculated olaparib IC50 were significantly reduced for all cell lines harbored BRCA1 or BRCA2 mutations compared to wild-type BRCA1/2 cells (P < 0.01). Furthermore, we observed a higher induction of apoptosis after 72 h olaparib treatment in BRCA-depleted cells than in wild-type cells. This strategy might offer new insights into the management of patients with pancreatic cancer and open up new perspectives based on the in vivo use of CRISPR/Cas9 strategy.

Recent Advances in In Vivo Somatic Cell Gene Modification in Newborn Pups

Germline manipulation at the zygote stage using the CRISPR/Cas9 system has been extensively employed for creating genetically modified animals and maintaining established lines. However, this approach requires a long and laborious task. Recently, many researchers have attempted to overcome these limitations by generating somatic mutations in the adult stage through tail vein injection or local administration of CRISPR reagents, as a new strategy called "in vivo somatic cell genome editing". This approach does not require manipulation of early embryos or strain maintenance, and it can test the results of genome editing in a short period. The newborn is an ideal stage to perform in vivo somatic cell genome editing because it is immune-privileged, easily accessible, and only a small amount of CRISPR reagents is required to achieve somatic cell genome editing throughout the entire body, owing to its small size. In this review, we summarize in vivo genome engineering strategies that have been successfully demonstrated in newborns. We also report successful in vivo genome editing through the neonatal introduction of genome editing reagents into various sites in newborns (as exemplified by intravenous injection via the facial vein), which will be helpful for creating models for genetic diseases or treating many genetic diseases.

A potential paradigm in CRISPR/Cas systems delivery: at the crossroad of microalgal gene editing and algal-mediated nanoparticles

Microalgae as the photosynthetic organisms offer enormous promise in a variety of industries, such as the generation of high-value byproducts, biofuels, pharmaceuticals, environmental remediation, and others. With the rapid advancement of gene editing technology, CRISPR/Cas system has evolved into an effective tool that revolutionised the genetic engineering of microalgae due to its robustness, high target specificity, and programmability. However, due to the lack of robust delivery system, the efficacy of gene editing is significantly impaired, limiting its application in microalgae. Nanomaterials have become a potential delivery platform for CRISPR/Cas systems due to their advantages of precise targeting, high stability, safety, and improved immune system. Notably, algal-mediated nanoparticles (AMNPs), especially the microalgae-derived nanoparticles, are appealing as a sustainable delivery platform because of their biocompatibility and low toxicity in a homologous relationship. In addition, living microalgae demonstrated effective and regulated distribution into specified areas as the biohybrid microrobots. This review extensively summarised the uses of CRISPR/Cas systems in microalgae and the recent developments of nanoparticle-based CRISPR/Cas delivery systems. A systematic description of the properties and uses of AMNPs, microalgae-derived nanoparticles, and microalgae microrobots has also been discussed. Finally, this review highlights the challenges and future research directions for the development of gene-edited microalgae.