Scaffold-mediated non-viral delivery platform for CRISPR/Cas9-based genome editing

Advances in biomaterials for oral-maxillofacial bone regeneration: spotlight on periodontal and alveolar bone strategies

The intricate nature of oral-maxillofacial structure and function, coupled with the dynamic oral bacterial environment, presents formidable obstacles in addressing the repair and regeneration of oral-maxillofacial bone defects. Numerous characteristics should be noticed in oral-maxillofacial bone repair, such as irregular morphology of bone defects, homeostasis between hosts and microorganisms in the oral cavity and complex periodontal structures that facilitate epithelial ingrowth. Therefore, oral-maxillofacial bone repair necessitates restoration materials that adhere to stringent and specific demands. This review starts with exploring these particular requirements by introducing the particular characteristics of oral-maxillofacial bones and then summarizes the classifications of current bone repair materials in respect of composition and structure. Additionally, we discuss the modifications in current bone repair materials including improving mechanical properties, optimizing surface topography and pore structure and adding bioactive components such as elements, compounds, cells and their derivatives. Ultimately, we organize a range of potential optimization strategies and future perspectives for enhancing oral-maxillofacial bone repair materials, including physical environment manipulation, oral microbial homeostasis modulation, osteo-immune regulation, smart stimuli-responsive strategies and multifaceted approach for poly-pathic treatment, in the hope of providing some insights for researchers in this field. In summary, this review analyzes the complex demands of oral-maxillofacial bone repair, especially for periodontal and alveolar bone, concludes multifaceted strategies for corresponding biomaterials and aims to inspire future research in the pursuit of more effective treatment outcomes.

Scaffold-based non-viral CRISPR delivery platform for efficient and prolonged gene activation to accelerate tissue regeneration

Clustered regularly interspaced short palindromic repeat activation (CRISPRa) technology has emerged as a precise genome editing tool for activating endogenous transgene expression. While it holds promise for precise cell modification, its translation into tissue engineering has been hampered by biosafety concerns and suboptimal delivery methods. To address these challenges, we have developed a CRISPRa non-viral gene delivery platform by immobilizing non-viral CRISPRa complexes into a biocompatible hydrogel/nanofiber (Gel/NF) composite scaffold. The Gel/NF scaffold facilitates the controlled and sustained release of CRISPRa complexes and also promotes cell recruitment to the scaffold for efficient and localized transfection. As a proof of concept, we employed this CRISPRa delivery platform to activate the vascular endothelial growth factor (VEGF) gene in a rat model with full-thickness skin defects. Our results demonstrate sustained upregulation of VEGF expression even at 21 days post-implantation, resulting in enhanced angiogenesis and improved skin regeneration. These findings underscore the potential of the Gel/NF scaffold-based CRISPRa delivery platform as an efficient and durable strategy for gene activation, offering promising prospects for tissue regeneration. STATEMENT OF SIGNIFICANCE: Translation of clustered regularly interspaced short palindromic repeat activation (CRISPRa) therapy to tissue engineering is limited by biosafety concerns and unsatisfactory delivery strategy. To solve this issue, we have developed a CRISPRa non-viral gene delivery platform by immobilizing non-viral CRISPRa complexes into a biocompatible hydrogel/nanofiber (Gel/NF) composite scaffold. This scaffold enables controlled and sustained release of CRISPRa and can induce cell recruitment for localized transfection. As a proof of concept, we activated vascular endothelial growth factor (VEGF) in a rat model with full-thickness skin defects, leading to sustained upregulation of VEGF expression, enhanced angiogenesis and improved skin regeneration in vivo. These findings demonstrate the potential of this platform for gene activation, thereby offering promising prospects for tissue regeneration.

Bioactive materials for in vivo sweat gland regeneration

Loss of sweat glands (SwGs) commonly associated with extensive skin defects is a leading cause of hyperthermia and heat stroke. In vivo tissue engineering possesses the potential to take use of the body natural ability to regenerate SwGs, making it more conducive to clinical translation. Despite recent advances in regenerative medicine, reconstructing SwG tissue with the same structure and function as native tissue remains challenging. Elucidating the SwG generation mechanism and developing biomaterials for in vivo tissue engineering is essential for understanding and developing in vivo SwG regenerative strategies. Here, we outline the cell biology associated with functional wound healing and the characteristics of bioactive materials. We critically summarize the recent progress in bioactive material-based cell modulation approaches for in vivo SwG regeneration, including the recruitment of endogenous cells to the skin lesion for SwG regeneration and in vivo cellular reprogramming for SwG regeneration. We discussed the re-establishment of microenvironment via bioactive material-mediated regulators. Besides, we offer promising perspectives for directing in situ SwG regeneration via bioactive material-based cell-free strategy, which is a simple and effective approach to regenerate SwG tissue with both fidelity of structure and function. Finally, we discuss the opportunities and challenges of in vivo SwG regeneration in detail. The molecular mechanisms and cell fate modulation of in vivo SwG regeneration will provide further insights into the regeneration of patient-specific SwGs and the development of potential intervention strategies for gland-derived diseases.

Local delivery of adeno-associated viral vectors with electrospun gelatin nanofiber mats

Adeno-associated viral (AAV) vectors play a significant role in gene therapy, yet the typical delivery methods, like systemic and local AAV injections, often lead to unintended off-target distribution and tissue damage due to injection. In this study, we propose a localized delivery approach for AAV vectors utilizing electrospun gelatin nanofiber mats, which are cross-linked with glutaraldehyde. The AAV vectors, which encoded a green fluorescent protein (GFP), were loaded onto the mats by immersing them in a solution containing the vectors. The amount of AAV vector loaded onto the mats increased as the vector concentration in the solution increased. The loaded AAV vector was steadily released into the cell culture medium over 3 days. The mats incubated for 3 days also showed the ability to transduce into the cells cultured on them. We evaluated the effectiveness of this delivery system by attaching the mats to mouse livers. GFP expression was visible on the surface of the liver beneath the attached mats, but not in areas in direct contact with the mats. These findings suggest that the attachment of AAV vector-loaded electrospun gelatin nanofiber mats to a target site present a promising solution for localized gene delivery while reducing off-target distribution.

Biomaterials-mediated CRISPR/Cas9 delivery: recent challenges and opportunities in gene therapy

The use of biomaterials in delivering CRISPR/Cas9 for gene therapy in infectious diseases holds tremendous potential. This innovative approach combines the advantages of CRISPR/Cas9 with the protective properties of biomaterials, enabling accurate and efficient gene editing while enhancing safety. Biomaterials play a vital role in shielding CRISPR/Cas9 components, such as lipid nanoparticles or viral vectors, from immunological processes and degradation, extending their effectiveness. By utilizing the flexibility of biomaterials, tailored systems can be designed to address specific genetic diseases, paving the way for personalized therapeutics. Furthermore, this delivery method offers promising avenues in combating viral illnesses by precisely modifying pathogen genomes, and reducing their pathogenicity. Biomaterials facilitate site-specific gene modifications, ensuring effective delivery to infected cells while minimizing off-target effects. However, challenges remain, including optimizing delivery efficiency, reducing off-target effects, ensuring long-term safety, and establishing scalable production techniques. Thorough research, pre-clinical investigations, and rigorous safety evaluations are imperative for successful translation from the laboratory to clinical applications. In this review, we discussed how CRISPR/Cas9 delivery using biomaterials revolutionizes gene therapy and infectious disease treatment, offering precise and safe editing capabilities with the potential to significantly improve human health and quality of life.

Electrospun fiber-mediated delivery of neurotrophin-3 mRNA for neural tissue engineering applications

Aligned electrospun fibers provide topographical cues and local therapeutic delivery to facilitate robust peripheral nerve regeneration. mRNA delivery enables transient expression of desired proteins that promote axonal regeneration. However, no prior work delivers mRNA from electrospun fibers for peripheral nerve regeneration applications. Here, we developed the first aligned electrospun fibers to deliver pseudouridine-modified (Ψ) neurotrophin-3 (NT-3) mRNA (ΨNT-3mRNA) to primary Schwann cells and assessed NT-3 secretion and bioactivity. We first electrospun aligned poly(L-lactic acid) (PLLA) fibers and coated them with the anionic substrates dextran sulfate sodium salt (DSS) or poly(3,4-dihydroxy-L-phenylalanine) (pDOPA). Cationic lipoplexes containing ΨNT-3mRNA complexed to JetMESSENGER® were then immobilized to the fibers, resulting in detectable ΨNT-3mRNA release for 28 days from all fiber groups investigated (PLLA+mRNA, 0.5DSS4h+mRNA, and 2pDOPA4h+mRNA). The 2pDOPA4h+mRNA group significantly increased Schwann cell secretion of NT-3 for 21 days compared to control PLLA fibers (p < 0.001-0.05) and, on average, increased Schwann cell secretion of NT-3 by ≥ 2-fold compared to bolus mRNA delivery from the 1µgBolus+mRNA and 3µgBolus+mRNA groups. The 2pDOPA4h+mRNA fibers supported Schwann cell secretion of NT-3 at levels that significantly increased dorsal root ganglia (DRG) neurite extension by 44% (p < 0.0001) and neurite area by 64% (p < 0.001) compared to control PLLA fibers. The data show that the 2pDOPA4h+mRNA fibers enhance the ability of Schwann cells to promote neurite growth from DRG, demonstrating this platform's potential capability to improve peripheral nerve regeneration. STATEMENT OF SIGNIFICANCE: Aligned electrospun fibers enhance axonal regeneration by providing structural support and guidance cues, but further therapeutic stimulation is necessary to improve functional outcomes. mRNA delivery enables the transient expression of therapeutic proteins, yet achieving local, sustained delivery remains challenging. Previous work shows that genetic material delivery from electrospun fibers improves regeneration; however, mRNA delivery has not been explored. Here, we examine mRNA delivery from aligned electrospun fibers to enhance neurite outgrowth. We show that immobilization of NT-3mRNA/JetMESSENGER® lipoplexes to aligned electrospun fibers functionalized with pDOPA enables local, sustained NT-3mRNA delivery to Schwann cells, increasing Schwann cell secretion of NT-3 and enhancing DRG neurite outgrowth. This study displays the potential benefits of electrospun fiber-mediated mRNA delivery platforms for neural tissue engineering.

Atherosclerosis: The Involvement of Immunity, Cytokines and Cells in Pathogenesis, and Potential Novel Therapeutics

As a leading contributor to coronary artery disease (CAD) and stroke, atherosclerosis has become one of the major cardiovascular diseases (CVD) negatively impacting patients worldwide. The endothelial injury is considered to be the initial step of the development of atherosclerosis, resulting in immune cell migration and activation as well as inflammatory factor secretion, which further leads to acute and chronic inflammation. In addition, the inflammation and lipid accumulation at the lesions stimulate specific responses from different types of cells, contributing to the pathological progression of atherosclerosis. As a result, recent studies have focused on using molecular biological approaches such as gene editing and nanotechnology to mediate cellular response during atherosclerotic development for therapeutic purposes. In this review, we systematically discuss inflammatory pathogenesis during the development of atherosclerosis from a cellular level with a focus on the blood cells, including all types of immune cells, together with crucial cells within the blood vessel, such as smooth muscle cells and endothelial cells. In addition, the latest progression of molecular-cellular based therapy for atherosclerosis is also discussed. We hope this review article could be beneficial for the clinical management of atherosclerosis.

Gene editing strategies to treat lysosomal disorders: The example of mucopolysaccharidoses

Lysosomal storage disorders are a group of progressive multisystemic hereditary diseases with a combined incidence of 1:4,800. Here we review the clinical and molecular characteristics of these diseases, with a special focus on Mucopolysaccharidoses, caused primarily by the lysosomal storage of glycosaminoglycans. Different gene editing techniques can be used to ameliorate their symptoms, using both viral and nonviral delivery methods. Whereas these are still being tested in animal models, early results of phase I/II clinical trials of gene therapy show how this technology may impact the future treatment of these diseases. Hurdles related to specific hard-to-reach organs, such as the central nervous system, heart, joints, and the eye must be tackled. Finally, the regulatory framework necessary to advance into clinical practice is also discussed.

Gelatin nanofiber mats with Lipofectamine/plasmid DNA complexes for in vitro genome editing

Gelatin electrospun nanofiber mats are gaining interest for applications in biomaterials science, such as tissue engineering and drug/gene delivery systems. In this study, we report the use of electrospun gelatin nanofiber mats for plasmid DNA (pDNA) delivery. Gelatin nanofiber mats were insolubilized via cross-linking with glutaraldehyde. On the cross-linked mats, human embryonic kidney-derived HEK293 cells demonstrated high viability for 7 days of culture (>95%) and were able to proliferate during that time. The Lipofectamine/pDNA complexes were immobilized on the mats through immersion in a solution, and HEK293 cells cultured on these mats expressed GFP for 7 days. Furthermore, HEK293 cells did not express GFP via the pDNA complexes released from the mats because the ability to deliver pDNA into the cells was lost. Since the mats could be used to transfect multiple types of pDNA into the cells simultaneously, we have achieved targeted genome editing using the mats. These data highlight the potential of gelatin nanofiber mats with Lipofectamine/pDNA complexes for local gene therapy via pDNA delivery as well as genome editing.

Carrier strategies boost the application of CRISPR/Cas system in gene therapy

Emerging clustered regularly interspaced short palindromic repeat/associated protein (CRISPR/Cas) genome editing technology shows great potential in gene therapy. However, proteins and nucleic acids suffer from enzymatic degradation in the physiological environment and low permeability into cells. Exploiting carriers to protect the CRISPR system from degradation, enhance its targeting of specific tissues and cells, and reduce its immunogenicity is essential to stimulate its clinical applications. Here, the authors review the state-of-the-art CRISPR delivery systems and their applications, and describe strategies to improve the safety and efficacy of CRISPR mediated genome editing, categorized by three types of cargo formats, that is, Cas: single-guide RNA ribonucleoprotein, Cas mRNA and single-guide RNA, and Cas plasmid expressing CRISPR/Cas systems. The authors hope this review will help develop safe and efficient nanomaterial-based carriers for CRISPR tools.

Designing electrospun fiber platforms for efficient delivery of genetic material and genome editing tools

Electrospun fibers are versatile biomaterial platforms with great potential to support regeneration. Electrospun fiber characteristics such as fiber diameter, degree of alignment, rate of degradation, and surface chemistry enable the creation of unique, tunable scaffolds for various drug or gene delivery applications. The delivery of genetic material and genome editing tools via viral and non-viral vectors are approaches to control cellular protein production. However, immunogenicity, off-target effects, and low delivery efficiencies slow the progression of gene delivery strategies to clinical settings. The delivery of genetic material from electrospun fibers overcomes such limitations by allowing for localized, tunable delivery of genetic material. However, the process of electrospinning is harsh, and care must be taken to retain genetic material bioactivity. This review presents an up-to-date summary of strategies to incorporate genetic material onto or within electrospun fiber platforms to improve delivery efficiency and enhance the regenerative potential of electrospun fibers for various tissue engineering applications.

Nucleic Acid Delivery from Granular Hydrogels

Nucleic acid delivery has applications ranging from tissue engineering to vaccine development to infectious disease. Cationic polymer condensed nucleic acids are used with surface-coated porous scaffolds and are able to promote long-term gene expression. However, due to surface loading of the scaffold, there is a limit to the amount of nucleic acid that can be loaded, resulting in decreasing expression rate over time. In addition, surface-coated scaffolds are generally non-injectable. Here, it is demonstrated that cationic polymer condensed nucleic acids can be effectively loaded into injectable granular hydrogel scaffolds by stabilizing the condensed nucleic acid into a lyophilized powder, loading the powder into a bulk hydrogel, and then fragmenting the loaded hydrogel. The resulting hydrogel microparticles contain non-aggregated nucleic acid particles, can be annealed post-injection to result in an injectable microporous hydrogel, and can effectively deliver nucleic acids to embedded cells with a constant expression rate. Due to the nature of granular hydrogels, it is demonstrated that mixtures of loaded and unloaded particles and spatially resolved gene expression can be easily achieved. The ability to express genes long term from an injectable porous hydrogel will further open the applications of nucleic acid delivery.

CRISPR-Cas12a-regulated DNA adsorption and metallization on MXenes as enhanced enzyme mimics for sensitive colorimetric detection of hepatitis B virus DNA

Hepatitis B virus (HBV) infection is closely associated with the high risk of evolving into human hepatitis diseases including chronic hepatitis, liver fibrosis and cirrhosis, as well as hepatoma. Although various methods have been developed for HBV DNA detection, most of them either rely on expensive instruments or laborious procedures involving professional personnel. In this study, we for the first time established the CRISPR-Cas12a based colorimetric biosensor for target HBV detection by utilizing probe DNA regulation of the catalytic behaviors of Mxene-probe DNA-Ag/Pt nanohybrids. In the presence of HBV target, the Cas12a trans-cleavage activity could be efficiently activated to degrade the DNA probes, which led to the inhibition of DNA metallization and enzyme activity enhancer DNA adsorbed on Mxene, resulting in significantly reduced catalytic activity. The Mxene-probe DNA-Ag/Pt nanohybrids exhibited excellent sensitivity and specificity with subpicomolar detection limits, as well as good accuracy and stability for the determination of target HBV DNA in human serum samples. Moreover, this colorimetric sensing strategy could be integrated with the smartphone platform to allow the visible sensitive detection of target DNA. Taken together, the proposed colorimetric method provides a novel approach for HBV DNA diagnosis, especially suitable for the high endemic, developing countries with limited instrumental and medical supports.

Calcium-based nanomaterials and their interrelation with chitosan: optimization for pCRISPR delivery

There have been numerous advancements in the early diagnosis, detection, and treatment of genetic diseases. In this regard, CRISPR technology is promising to treat some types of genetic issues. In this study, the relationship between calcium (due to its considerable physicochemical properties) and chitosan (as a natural linear polysaccharide) was investigated and optimized for pCRISPR delivery. To achieve this, different forms of calcium, such as calcium nanoparticles (CaNPs), calcium phosphate (CaP), a binary blend of calcium and chitosan including CaNPs/Chitosan and CaP/Chitosan, as well as their tertiary blend including CaNPs-CaP/Chitosan, were prepared via both routine and green procedures using Salvia hispanica to reduce toxicity and increase nanoparticle stability (with a yield of 85%). Such materials were also applied to the human embryonic kidney (HEK-293) cell line for pCRISPR delivery. The results were optimized using different characterization techniques demonstrating acceptable binding with DNA (for both CaNPs/Chitosan and CaNPs-CaP/Chitosan) significantly enhancing green fluorescent protein (EGFP) (about 25% for CaP/Chitosan and more than 14% for CaNPs-CaP/Chitosan).

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40097-021-00446-1.

Emerging 2D Nanomaterials for Biomedical Applications

Two-dimensional (2D) nanomaterials are an emerging class of biomaterials with remarkable potential for biomedical applications. The planar topography of these nanomaterials confers unique physical, chemical, electronic and optical properties, making them attractive candidates for therapeutic delivery, biosensing, bioimaging, regenerative medicine, and additive manufacturing strategies. The high surface-to-volume ratio of 2D nanomaterials promotes enhanced interactions with biomolecules and cells. A range of 2D nanomaterials, including transition metal dichalcogenides (TMDs), layered double hydroxides (LDHs), layered silicates (nanoclays), 2D metal carbides and nitrides (MXenes), metal-organic framework (MOFs), covalent organic frameworks (COFs) and polymer nanosheets have been investigated for their potential in biomedical applications. Here, we will critically evaluate recent advances of 2D nanomaterial strategies in biomedical engineering and discuss emerging approaches and current limitations associated with these nanomaterials. Due to their unique physical, chemical, and biological properties, this new class of nanomaterials has the potential to become a platform technology in regenerative medicine and other biomedical applications.

Stem Cell-Derived Nanovesicles: A Novel Cell-Free Therapy for Wound Healing

Wound healing and regeneration are a dynamic and complex process that requires a collaborative effort between growth factors, epidermal cells, dermal cells, extracellular matrix, and vessels local to the wound area. Mesenchymal stem cells participate in the recruitment site, mainly by releasing secretory factors and matrix proteins to promote wound healing. Stem cell-derived nanovesicles (CDNs), including microvesicles, exosomes, and exosome mimetics, contain most of the biologically active substances of their parent cells and have similar effects. CDNs can shuttle various proteins, messenger RNAs, and microRNAs to regulate the activity of receptor cells, and they play important roles in skin wound healing. This article reviews recent research progress on CDNs for wound repair. We summarize current knowledge on how CDNs regulate immunity, fibroblast activity, angiogenesis, and scar formation in the wound healing process. This review can help researchers explore new treatment strategies to enhance the therapeutic efficacy of CDNs, which have a promising future as naturally cell-free therapies.

Enhanced efficiency of nonviral direct neuronal reprogramming on topographical patterns

Nonviral direct neuronal reprogramming holds significant potential in the fields of tissue engineering and regenerative medicine. However, the issue of low reprogramming efficiency poses a major barrier to its application. We propose that topographical cues, which have been applied successfully to enhance lineage-directed differentiation and multipotent stem cell transdifferentiation, could improve nonviral direct neuronal reprogramming efficiency. To investigate, we used a polymer-BAM (Brn2, Ascl1, Myt1l) factor transfection polypex to reprogram primary mouse embryonic fibroblasts. Using a multiarchitecture chip, we screened for patterns that may improve transfection and/or subsequent induced neuron reprogramming efficiency. Selected patterns were then investigated further by analyzing β-tubulin III (TUJ1) and microtubule-associated protein 2 (MAP2) protein expression, cell morphology and electrophysiological function of induced neurons. Certain hierarchical topographies, with nanopatterns imprinted on micropatterns, significantly improved the percentage of TUJ1+ and MAP2+ cells. It is postulated that the microscale base pattern enhances initial BAM expression while the nanoscale sub-pattern promotes subsequent maturation. This is because the base pattern alone increased expression of TUJ1 and MAP2, while the nanoscale pattern was the only pattern yielding induced neurons capable of firing multiple action potentials. Nanoscale patterns also produced the highest fraction of cells showing spontaneous synaptic activity. Overall, reprogramming efficiency with one dose of polyplex on hierarchical patterns was comparable to that of five doses without topography. Thus, topography can enhance nonviral direct reprogramming of fibroblasts into induced neurons.

Cell-free exosome-laden scaffolds for tissue repair

With the development of regenerative medicine, tissue repair at the molecular, cellular, tissue, and organ level has seen continuous improvements over traditional techniques. As the core of tissue repair, seed cells are widely used in various fields of regenerative medicine. However, their use is still associated with problems such as decreased cell survival and regeneration capacity after transplantation, immune rejection, and ethical concerns. Therefore, it is difficult to universally and safely apply stem cell banks for regenerative medicine. The paracrine effects of cells, especially secretion of exosomes, play vital roles in cell communication, immune response, angiogenesis, scar formation, tissue repair, and other biological functions. Exosomes are a type of nanoscale extracellular vesicle that contain biologically active molecules such as RNA and proteins; therefore, exosomes can replicate the functions of their parental cells. Meanwhile, exosomes can be used as nanocarriers to deliver active factors or small molecules to promote tissue repair. Preclinical studies of exosomes in tissue engineering and regenerative medicine have been carried in the fields of bone/cartilage repair, nerve regeneration, liver and kidney regeneration, skin repair, vascular tissue regeneration, etc. This review introduces exosomes from the aspects of biogenesis, composition, identification, and isolation, and focuses on the development status of scaffold materials for exosome delivery. In addition, we highlight examples of exosome-laden scaffolds for preclinical applications in tissue repair. We look forward to the broad application prospects of exosome-laden scaffolds.

Nanoparticle Delivery of CRISPR/Cas9 for Genome Editing

The emerging clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated system (Cas) gene-editing system represents a promising tool for genome manipulation. However, its low intracellular delivery efficiency severely compromises its use and potency for clinical applications. Nanocarriers, such as liposomes, polymers, and inorganic nanoparticles, have shown great potential for gene delivery. The remarkable development of nanoparticles as non-viral carriers for the delivery of the CRISPR/Cas9 system has shown great promise for therapeutic applications. In this review, we briefly summarize the delivery components of the CRISPR/Cas9 system and report on the progress of nano-system development for CRISPR/Cas9 delivery. We also compare the advantages of various nano-delivery systems and their applications to deliver CRISPR/Cas9 for disease treatment. Nano-delivery systems can be modified to fulfill the tasks of targeting cells or tissues. We primarily emphasize the novel exosome-based CRISPR/Cas9 delivery system. Overall, we review the challenges, development trends, and application prospects of nanoparticle-based technology for CRISPR/Cas9 delivery.

Scaffold-mediated CRISPR-Cas9 delivery system for acute myeloid leukemia therapy

Leukemia stem cells (LSCs) sustain the disease and contribute to relapse in acute myeloid leukemia (AML). Therapies that ablate LSCs may increase the chance of eliminating this cancer in patients. To this end, we used a bioreducible lipidoid-encapsulated Cas9/single guide RNA (sgRNA) ribonucleoprotein [lipidoid nanoparticle (LNP)-Cas9 RNP] to target the critical gene interleukin-1 receptor accessory protein (IL1RAP) in human LSCs. To enhance LSC targeting, we loaded LNP-Cas9 RNP and the chemokine CXCL12α onto mesenchymal stem cell membrane-coated nanofibril (MSCM-NF) scaffolds mimicking the bone marrow microenvironment. In vitro, CXCL12α release induced migration of LSCs to the scaffolds, and LNP-Cas9 RNP induced efficient gene editing. IL1RAP knockout reduced LSC colony-forming capacity and leukemic burden. Scaffold-based delivery increased the retention time of LNP-Cas9 in the bone marrow cavity. Overall, sustained local delivery of Cas9/IL1RAP sgRNA via CXCL12α-loaded LNP/MSCM-NF scaffolds provides an effective strategy for attenuating LSC growth to improve AML therapy.

Construction and purification of ANK gene deleted recombinant goatpox virus

Sheeppox virus (SPPV) and goatpox virus (GTPV) are two pathogens of host specificity. Previous studies have hypothesized that ankyrin (ANK) family may play an important role in determining host range of SPPV and GTPV. In order to verify the function of ANK proteins, it is critical to generate and purify the ANK gene deleted GTPV. In this study, the GFP gene as a reporter gene was connected with two homologous arms of ANK gene by fusion PCR. The ANK gene deleted transfer vectors were generated by inserting the PCR products into PET42b, and were transfected into testicular primary cells which were infected by GTPV. The rGTPV were identified as green fluorescence positive and properly purified. The results showed that GFP gene and two homologous arms of ANK gene were connected. The sequence was inserted in PET42b to form ANK deleted transfer vector. ANK deleted rGTPV was generated successfully by transferring vector and GTPV in cells. The ANK deleted rGTPV was purified and identified in this study. The study successfully generated the ANK deleted rGTPV. It overcomes the technical barrier for future studies about the function of ANK genes.

Scaffold-Based Delivery of CRISPR/Cas9 Ribonucleoproteins for Genome Editing

The simple and versatile CRISPR/Cas9 system is a promising strategy for genome editing in mammalian cells. Generally, the genome editing components, namely Cas9 protein and single-guide RNA (sgRNA), are delivered in the format of plasmids, mRNA, or ribonucleoprotein (RNP) complexes. In particular, non-viral approaches are desirable as they overcome the safety concerns posed by viral vectors. To control cell fate for tissue regeneration, scaffold-based delivery of genome editing components will offer a route for local delivery and provide possible synergistic effects with other factors such as topographical cues that are co-delivered by the same scaffold. In this chapter, we detail a simple method of surface modification to functionalize electrospun nanofibers with CRISPR/Cas9 RNP complexes. The mussel-inspired bio-adhesive coating will be used as it is a simple and effective method to immobilize biomolecules on the surface. Nanofibers will provide a biomimicking microenvironment and topographical cues to seeded cells. For evaluation, a model cell line with single copies of enhanced green fluorescent protein (U2OS.EGFP) will be used to validate the efficiency of gene disruption.

Strategies in the delivery of Cas9 ribonucleoprotein for CRISPR/Cas9 genome editing

CRISPR/Cas9 genome editing has gained rapidly increasing attentions in recent years, however, the translation of this biotechnology into therapy has been hindered by efficient delivery of CRISPR/Cas9 materials into target cells. Direct delivery of CRISPR/Cas9 system as a ribonucleoprotein (RNP) complex consisting of Cas9 protein and single guide RNA (sgRNA) has emerged as a powerful and widespread method for genome editing due to its advantages of transient genome editing and reduced off-target effects. In this review, we summarized the current Cas9 RNP delivery systems including physical approaches and synthetic carriers. The mechanisms and beneficial roles of these strategies in intracellular Cas9 RNP delivery were reviewed. Examples in the development of stimuli-responsive and targeted carriers for RNP delivery are highlighted. Finally, the challenges of current Cas9 RNP delivery systems and perspectives in rational design of next generation materials for this promising field will be discussed.

Oriented and sustained protein expression on biomimicking electrospun fibers for evaluating functionality of cells

A proper protein orientation is often required in order to achieve specific protein-receptor interaction to elicit a desired biological response. Here, we present a Protein A-based biomimicking platform that is capable of efficiently orienting proteins for evaluating cellular behaviour. By absorbing Protein A onto aligned bio-mimicking polycaprolactone (PCL) fibers, we demonstrate that protein binding could be retained on these fibers for at least 7 days under physiologically relevant conditions. We further show that Protein A served as a molecular orientor to arrange the recombinant proteins in similar orientations. Such protein-orienting scaffolds were further verified to be biologically functional by using sensitive primary rat cortical neurons (CNs) and oligodendrocyte progenitor cells (OPCs), as model neural cells for a stringent proof of concept. Specifically, CNs that were seeded on fibers coated with Protein A and a known enhancer of neurite growth (L1 Cell Adhesion Molecular L1CAM) displayed the longest total neurite length (462.77 ± 100.79 μm, p < 0.001) as compared to the controls. Besides that, OPCs seeded on fibers coated with Protein A and Neuregulin-1 Type III (Nrg1 type III) (myelin enhancer) produced the longest myelin ensheathment length (19.8 ± 11.69 μm). These results demonstrate the efficacy of this platform for protein screening applications.

Coassembly of nucleus-targeting gold nanoclusters with CRISPR/Cas9 for simultaneous bioimaging and therapeutic genome editing

The clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (CRISPR/Cas9) technology enables genome editing with high precision and versatility and has been widely utilized to combat viruses, bacteria, cancers, and genetic diseases. Nonviral nanocarriers can overcome several limitations of viral vehicles, including immunogenicity, inflammation, carcinogenicity, and low versatility, and thus represent promising platforms for CRISPR/Cas9 delivery. Herein, we for the first time develop the application of protamine-capped gold nanoclusters (protamine-AuNCs) as an effective nanocarrier for Cas9-sgRNA plasmid transport and release to achieve efficient genome editing. The protamine-AuNCs integrate the merits of AuNCs and protamine: AuNCs are able to promptly assemble with Cas9-sgRNA plasmids to allow efficient cellular delivery, while the cationic protamine facilitates the effective release of Cas9-sgRNA plasmids into the cellular nucleus. The AuNCs/Cas9-gRNA plasmid nanocomplexes can not only achieve successful gene editing in cells but also knock out the oncogenic gene for cancer therapy. Moreover, the AuNCs with excellent photoluminescence characteristics endow our nanoplatform with the functionality of bioimaging. Overall, our study provides strong evidence that demonstrates protamine-AuNCs as an effective CRISPR/Cas9 delivery tool for gene therapy.

The Synergy between CRISPR and Chemical Engineering

Gene therapy and transgenic research have advanced quickly in recent years due to the development of CRISPR technology. The rapid development of CRISPR technology has been largely benefited by chemical engineering. Firstly, chemical or synthetic substance enables spatiotemporal and conditional control of Cas9 or dCas9 activities. It prevents the leaky expression of CRISPR components, as well as minimizes toxicity and off-target effects. Multi-input logic operations and complex genetic circuits can also be implemented via multiplexed and orthogonal regulation of target genes. Secondly, rational chemical modifications to the sgRNA enhance gene editing efficiency and specificity by improving sgRNA stability and binding affinity to on-target genomic loci, and hence reducing off-target mismatches and systemic immunogenicity. Chemically-modified Cas9 mRNA is also more active and less immunogenic than the native mRNA. Thirdly, nonviral vehicles can circumvent the challenges associated with viral packaging and production through the delivery of Cas9-sgRNA ribonucleoprotein complex or large Cas9 expression plasmids. Multi-functional nanovectors enhance genome editing in vivo by overcoming multiple physiological barriers, enabling ligand-targeted cellular uptake, and blood-brain barrier crossing. Chemical engineering can also facilitate viral-based delivery by improving vector internalization, allowing tissue-specific transgene expression, and preventing inactivation of the viral vectors in vivo. This review aims to discuss how chemical engineering has helped improve existing CRISPR applications and enable new technologies for biomedical research. The usefulness, advantages, and molecular action for each chemical engineering approach are also highlighted.

Nanotechnological Strategies for Osteoarthritis Diagnosis, Monitoring, Clinical Management, and Regenerative Medicine: Recent Advances and Future Opportunities

PURPOSE OF REVIEW

In this review article, we discuss the potential for employing nanotechnological strategies for the diagnosis, monitoring, and clinical management of osteoarthritis (OA) and explore how nanotechnology is being integrated rapidly into regenerative medicine for OA and related osteoarticular disorders.

RECENT FINDINGS

We review recent advances in this rapidly emerging field and discuss future opportunities for innovations in enhanced diagnosis, prognosis, and treatment of OA and other osteoarticular disorders, the smart delivery of drugs and biological agents, and the development of biomimetic regenerative platforms to support cell and gene therapies for arresting OA and promoting cartilage and bone repair. Nanotubes, magnetic nanoparticles, and other nanotechnology-based drug and gene delivery systems may be used for targeting molecular pathways and pathogenic mechanisms involved in OA development. Nanocomposites are also being explored as potential tools for promoting cartilage repair. Nanotechnology platforms may be combined with cell, gene, and biological therapies for the development of a new generation of future OA therapeutics. Graphical Abstract.