Bioinspired nanogels as cell-free DNA trapping and scavenging organelles for rheumatoid arthritis treatment.

Excessive cell-free DNA (cfDNA) in the serum and synovium is considered a causative factor of rheumatoid arthritis (RA). Thus, cfDNA scavenging by using cationic polymers has been an effective therapeutic avenue, while these stratagems still suffer from systemic toxicity and unstable capture of cfDNA. Here, inspired by the biological charge-trapping effects and active degradation function of enzyme-containing organelles in vivo, we proposed a cationic peptide dendrimer nanogel with deoxyribonuclease I (DNase I) conjugation for the treatment of RA. Benefitting from their naturally derived peptide components, the resultant nanogels were highly biocompatible. More attractively, by tailoring them with a larger size and higher surface charge density, these cationic nanogels could achieve the fastest targeting capability, highest accumulation amounts, longer persistence time, and superior DNA scavenging capacity in inflamed joints. Based on these features, we have demonstrated that the organelle mimicking cationic nanogels could significantly down-regulate toll-like receptor (TLR)-9 signaling pathways and attenuate RA symptoms in collagen-induced arthritis mice. These results make the bioinspired DNase I conjugated cationic nanogels an ideal candidate for treating RA and other immune dysregulation diseases.

Recent advances in biomaterial-boosted adoptive cell therapy.

Adoptive immunotherapies based on the transfer of functional immune cells hold great promise in treating a wide range of malignant diseases, especially cancers, autoimmune diseases, and infectious diseases. However, manufacturing issues and biological barriers lead to the insufficient population of target-selective effector cells at diseased sites after adoptive transfer, hindering effective clinical translation. The convergence of immunology, cellular biology, and materials science lays a foundation for developing biomaterial-based engineering platforms to overcome these challenges. Biomaterials can be rationally designed to improve ex vivo immune cell expansion, expedite functional engineering, facilitate protective delivery of immune cells in situ, and navigate the infused cells in vivo. Herein, this review presents a comprehensive summary of the latest progress in biomaterial-based strategies to enhance the efficacy of adoptive cell therapy, focusing on function-specific biomaterial design, and also discusses the challenges and prospects of this field.

Artificial Lipids and Macrophage Membranes Coassembled Biomimetic Nanovesicles for Antibacterial Treatment.

Tissue bacterial infections are a major pathological factor in many diseases. Effects on this aspect are in focus for the development of coordinated therapeutic strategies for bacterial killing and anti-inflammation. Here, inspired by the biodetoxification capacity of immune cells, multifunctional biomimetic nanovesicles (MϕM-LPs) that are co-assembled by macrophage membranes and artificial lipids to deliver antibiotics for treating bacterial infections, are presented. The macrophage membrane endows the MϕM-LPs with the capacity of lipopolysaccharide and inflammatory cytokine neutralization, while the artificial lipid membrane can be further engineered to increase the fluidity and anchor to bacteria. In addition, the MϕM-LPs can deliver sufficient ciprofloxacin with controllable release to accomplish an excellent antibacterial activity and biodetoxification capacity in vitro. Based on these advantages, it is demonstrated in a mouse model of Staphylococcus aureus (S. aureus) focal infection, that a single injection of the biomimetic nanovesicles can effectively anchor to and eliminate S. aureus in the infected tissue and reduce inflammatory cytokine levels. Thus, the tissue regeneration and collagen deposition can be accelerated. These results indicate the potential values of integrating natural and artificial membrane materials as a multifunctional biomimetic drug delivery system to treat bacterial infections.

Block Length-Dependent Protein Fouling on Poly(2-oxazoline)-Based Polymersomes: Influence on Macrophage Association and Circulation Behavior.

Polymersomes are vesicular structures self-assembled from amphiphilic block copolymers and are considered an alternative to liposomes for applications in drug delivery, immunotherapy, biosensing, and as nanoreactors and artificial organelles. However, the limited availability of systematic stability, protein fouling (protein corona formation), and blood circulation studies hampers their clinical translation. Poly(2-oxazoline)s (POx) are valuable antifouling hydrophilic polymers that can replace the current gold-standard, poly(ethylene glycol) (PEG), yet investigations of POx functionality on nanoparticles are relatively sparse. Herein, a systematic study is reported of the structural, dynamic and antifouling properties of polymersomes made of poly(2-methyl-2-oxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyl-2-oxazoline) (PMOXA-b-PDMS-b-PMOXA). The study relates in vitro antifouling performance of the polymersomes to atomistic molecular dynamics simulations of polymersome membrane hydration behavior. These observations support the experimentally demonstrated benefit of maximizing the length of PMOXA (degree of polymerization (DP) > 6) while keeping PDMS at a minimal length that still provides sufficient membrane stability (DP > 19). In vitro macrophage association and in vivo blood circulation evaluation of polymersomes in zebrafish embryos corroborate these findings. They further suggest that single copolymer presentation on polymersomes is outperformed by blends of varied copolymer lengths. This study helps to rationalize design rules for stable and low-fouling polymersomes for future medical applications.

Reactive Microneedle Patches with Antibacterial and Dead Bacteria-Trapping Abilities for Skin Infection Treatment.

Bacterial skin infections are highly prevalent and pose a significant public health threat. Current strategies are primarily focused on the inhibition of bacterial activation while disregarding the excessive inflammation induced by dead bacteria remaining in the body and the effect of the acidic microenvironment during therapy. In this study, a novel dual-functional MgB2 microparticles integrated microneedle (MgB2 MN) patch is presented to kill bacteria and eliminate dead bacteria for skin infection management. The MgB2 microparticles not only can produce a local alkaline microenvironment to promote the proliferation and migration of fibroblasts and keratinocytes, but also achieve >5 log bacterial inactivation. Besides, the MgB2 microparticles effectively mitigate dead bacteria-induced inflammation through interaction with lipopolysaccharide (LPS). With the incorporation of these MgB2 microparticles, the resultant MgB2 MN patches effectively kill bacteria and capture dead bacteria, thereby mitigating these bacteria-induced inflammation. Therefore, the MgB2 MN patches show good therapeutic efficacy in managing animal bacterial skin infections, including abscesses and wounds. These results indicate that reactive metal borides-integrated microneedle patches hold great promise for the treatment of clinical skin infections.

Dexamethasone-Integrated Mesenchymal Stem Cells for Systemic Lupus Erythematosus Treatment via Multiple Immunomodulatory Mechanisms.

The therapeutic application of mesenchymal stem cells (MSCs) has good potential as a treatment strategy for systemic lupus erythematosus (SLE), but traditional MSC therapy still has limitations in effectively modulating immune cells. Herein, we present a promising strategy based on dexamethasone liposome-integrated MSCs (Dexlip-MSCs) for treating SLE via multiple immunomodulatory pathways. This therapeutic strategy prolonged the circulation time of dexamethasone liposomes in vivo, restrained CD4+T-cell proliferation, and inhibited the release of proinflammatory mediators (IFN-γ and TNF-α) by CD4+T cells. In addition, Dexlip-MSCs initiated cellular reprogramming by activating the glucocorticoid receptor (GR) signaling pathway to upregulate the expression of anti-inflammatory factors such as cysteine-rich secretory protein LCCL-containing domain 2 (CRISPLD2) and downregulate the expression of proinflammatory factors. In addition, Dexlip-MSCs synergistically increased the anti-inflammatory inhibitory effect of CD4+T cells through the release of dexamethasone liposomes or Dex-integrated MSC-derived exosomes (Dex-MSC-EXOs). Based on these synergistic biological effects, we demonstrated that Dexlip-MSCs alleviated disease progression in MRL/lpr mice more effectively than Dexlip or MSCs alone. These features indicate that our stem cell delivery strategy is a promising therapeutic approach for clinical SLE treatment.

Enhanced Antimalarial and Antisequestration Activity of Methoxybenzenesulfonate-Modified Biopolymers and Nanoparticles for Tackling Severe Malaria.

Severe malaria is a life-threatening condition that is associated with a high mortality. Severe Plasmodium falciparum infections are mediated primarily by high parasitemia and binding of infected red blood cells (iRBCs) to the blood vessel endothelial layer, a process known as sequestration. Here, we show that including the 5-amino-2-methoxybenzenesulfonate (AMBS) chemical modification in soluble biopolymers (polyglutamic acid and heparin) and poly(acrylic acid)-exposing nanoparticles serves as a universal tool to introduce a potent parasite invasion inhibitory function in these materials. Importantly, the modification did not add or eliminated (for heparin) undesired anticoagulation activity. The materials protected RBCs from invasion by various parasite strains, employing both major entry pathways. Two further P. falciparum strains, which either expose ligands for chondroitin sulfate A (CSA) or intercellular adhesion molecule 1 (ICAM-1) on iRBCs, were tested in antisequestration assays due to their relevance in placental and cerebral malaria, respectively. Antisequestration activity was found to be more efficacious with nanoparticles vs gold-standard soluble biopolymers (CSA and heparin) against both strains, when tested on receptor-coated dishes. The nanoparticles also efficiently inhibited and reversed the sequestration of iRBCs on endothelial cells. First, the materials described herein have the potential to reduce the parasite burden by acting at the key multiplication stage of reinvasion. Second, the antisequestration ability could help remove iRBCs from the blood vessel endothelium, which could otherwise cause vessel obstruction, which in turn can lead to multiple organ failure in severe malaria infections. This approach represents a further step toward creation of adjunctive therapies for this devastating condition to reduce morbidity and mortality.

Neutrophil-Mediated Nanozyme Delivery System for Acute Kidney Injury Therapy.

Reactive oxygen species (ROS) scavenging of nanozymes toward acute kidney injury (AKI) is a current promising strategy, however, the glomerular filtration barrier (GFB) limits their application for treating kidney related diseases. Here, a neutrophil-mediated delivery system able to hijack neutrophil to transport nanozyme-loaded cRGD-liposomes to inflamed kidney for AKI treatment by cRGD targeting integrin αvß1 is reported. The neutrophil-mediated nanozyme delivery system demonstrated great antioxidant and anti-apoptosis ability in HK-2 and NRK-52E cell lines. Moreover, in ischemia-reperfusion (I/R) induced AKI mice, a single dose of LM@cRGD-LPs 12 h post-ischemia significantly reduces renal function indicators, alleviates renal pathological changes, and inhibits apoptosis of renal tubular cells and the expression of renal tubular injured marker, thus remarkably reducing the damage of AKI. Mechanistically, the treatment of LM@cRGD-LPs markedly inhibits the process of Nrf2 to the nucleus and reduces the expression of the downstream HO-1, achieves a 99.51% increase in renal tissue Nrf2 levels, and an 86.31% decrease in HO-1 levels after LM@cRGD-LPs treatment. In short, the strategy of neutrophil-mediated nanozyme delivery system hold great promise as a potential therapy for AKI or other inflammatory diseases.

Emerging antibacterial nanozymes for wound healing.

Wound infections continuously impose a huge economic and social burden on public healthcare. Despite the effective treatment of bacteria-infected wounds after using traditional antibiotics, the misuse of antibiotics usually causes the spread of bacterial resistance and decreases therapeutic outcomes. Therefore, the development of efficient antibacterial agents is urgently needed. Nanozymes, as a new generation of artificial enzymes, combine the intrinsic abilities of nanomaterials and natural enzymes. Recently, nanozymes has been widely developed to kill bacteria and treat wound infections by catalyzing the generation of various reactive oxygen species. Thus, this new concept of "antibacterial nanozymes" will promote the further advances of connecting nanozymes and bacterial elimination. To highlight these achievements, we summarize different types of antibacterial nanozymes for wound healing. It is believed that such a promising therapeutic strategy of developing antibacterial nanozymes will make a great contribution in the field of skin regeneration. We expect that antibacterial nanozymes will play the significant roles in both basic research and clinical applications.

Stem cell niche-inspired microcarriers with ADSCs encapsulation for diabetic wound treatment.

Stem cell therapies have made great progress in the treatment of diabetic wounds during recent decades, while their short in vivo residence, alloimmune reactions, undesired behaviors, and dramatic losses of cell functions still hinder the translation of them into clinic. Here, inspired by the natural components of stem cell niches, we presented novel microfluidic hydrogel microcarriers with extracellular matrix (ECM)-like composition and adipose-derived stem cells (ADSCs) encapsulation for diabetic wound healing. As the hydrogel was synthesized by conjugating hyaluronic acid methacryloyl (HAMA) onto the Fibronectin (FN) molecule chain (FN-HAMA), the laden ADSCs in the microcarriers showed improved bioactivities and pro-regenerative capabilities. Based on these features, we have demonstrated that these ADSCs microcarriers exhibited significant promotion of neovascularization, follicular rejuvenation, and collagen deposition in a mouse diabetic wound model. These results indicated that the stem cell niche-inspired FN-HAMA microcarriers with ADSCs encapsulation have great clinical potential for diabetic wound treatment.

Artificial Periosteum with Oriented Surface Nanotopography and High Tissue Adherent Property.

Massive periosteal defects often significantly impair bone regeneration and repair, which have become a major clinical challenge. Unfortunately, current engineered periosteal materials can hardly currently focus on achieving high tissue adhesion property, being suitable for cell growth, and inducing cell orientation concurrently to meet the properties of nature periosteum. Additionally, the preparation of oriented surface nanotopography often relies on professional equipment. In this study, inspired by the oriented collagen structure of nature periosteum, we present a composite artificial periosteum with a layer of oriented nanotopography surface containing carbon nanotubes (CNTs), cross-linked with adhesive polydopamine (PDA) hydrogel on both terminals. An oriented surface structure that can simulate the oriented alignment of periosteal collagen fibers can be quickly and conveniently obtained via a simple stretching of the membrane in a water bath. With the help of CNTs, our artificial periosteum exhibits sufficient mechanical strength and desired oriented nanotopological structure surface, which further induces the directional arrangement of human bone marrow mesenchymal stem cells (hBMSCs) on the membrane. These oriented hBMSCs express significantly higher levels of osteogenic genes and proteins, while the resultant composite periosteum can be stably immobilized in vivo in the rat model of massive calvarial defect through the PDA hydrogel, which finally shows promising bone regeneration ability. We anticipate that the developed functional artificial periosteum has great potential in biomedical applications for the treatment of composite defects of the bone and periosteum.

A CT-Based Deep Learning Radiomics Nomogram to Predict Histological Grades of Head and Neck Squamous Cell Carcinoma.

RATIONALE AND OBJECTIVES: Accurate pretreatment assessment of histological differentiation grade of head and neck squamous cell carcinoma (HNSCC) is crucial for prognosis evaluation. This study aimed to construct and validate a contrast-enhanced computed tomography (CECT)-based deep learning radiomics nomogram (DLRN) to predict histological differentiation grades of HNSCC. MATERIALS AND METHODS: A total of 204 patients with HNSCC who underwent CECT scans were enrolled in this study. The participants recruited from two hospitals were split into a training set (n=124, 74 well/moderately differentiated and 50 poorly differentiated) of patients from one hospital and an external test set of patients from the other hospital (n=80, 49 well/moderately differentiated and 31 poorly differentiated). CECT-based manually-extracted radiomics (MER) features and deep learning (DL) features were extracted and selected. The selected MER features and DL features were then combined to construct a DLRN via multivariate logistic regression. The predictive performance of the DLRN was assessed using ROCs and decision curve analysis (DCA). RESULTS: Three MER features and seven DL features were finally selected. The DLRN incorporating the selected MER and DL features showed good predictive value for the histological differentiation grades of HNSCC (well/moderately differentiated vs. poorly differentiated) in both the training (AUC, 0.878) and test (AUC, 0.822) sets. DCA demonstrated that the DLRN was clinically useful for predicting histological differentiation grades of HNSCC. CONCLUSION: A CECT-based DLRN was constructed to predict histological differentiation grades of HNSCC. The DLRN showed good predictive efficacy and might be useful for prognostic evaluation of patients with HNSCC.

CD47- and Integrin α4/ß1-Comodified-Macrophage-Membrane-Coated Nanoparticles Enable Delivery of Colchicine to Atherosclerotic Plaque.

Atherosclerosis is a chronic inflammatory disease and the major pathological factor of most cardiovascular diseases, leading to ≈1/3 of deaths worldwide. Improving local delivery of anti-inflammatory drugs to the site of atherosclerosis has significant promise to prevent the development of atherosclerotic plaque clinically. Here, a modified-macrophage-membrane-coated nanoparticle drug delivery able to transport colchicine to the atherosclerotic site is reported. This hybrid system efficiently targets endothelial cells under an inflammatory environment while escaping the endocytosis of macrophages. Furthermore, the anti-inflammatory effect of the modified-macrophage-membrane-coated nanoparticles on foam cells is studied. In vivo, the migration of the modified-macrophage-membrane-coated nanoparticles to atherosclerotic lesions is confirmed in a vulnerable atherosclerotic plaque mouse model. Intravenous injections of the hybrid system successfully reduce the lipid plaque load and improve the plaque stability. This strategy provides a potential therapeutic system for the targeted delivery of anti-inflammatory drugs to the atherosclerotic site for the treatment of atherosclerosis in cardiovascular diseases.

Presentation of antigen on extracellular vesicles using transmembrane domains from viral glycoproteins for enhanced immunogenicity.

A vaccine antigen, when launched as DNA or RNA, can be presented in various forms, including intracellular, secreted, membrane-bound, or on extracellular vesicles (EVs). Whether an antigen in one or more of these forms is superior in immune induction remains unclear. In this study, we used GFP as a model antigen and first compared the EV-loading efficiency of transmembrane domains (TMs) from various viral glycoproteins, and then investigated whether EV-bound GFP (EV-GFP) would enhance immune induction. Our data showed that GFP fused to viral TMs was successfully loaded onto the surface of EVs. In addition, GFP-bound EVs were predominantly associated with the exosome marker CD81. Immunogenicity study with EV-GFP-producing plasmids in mice demonstrated that antigen-specific IgG and IgA were significantly increased in EV-GFP groups, compared to soluble and intracellular GFP groups. Similarly, GFP-specific T cell response-related cytokines produced by antigen-stimulated splenocytes were also enhanced in mice immunized with EV-GFP constructs. Immunogenicity study with purified soluble GFP and GFP EVs further confirmed the immune enhancement property of EV-GFP in mice. In vitro uptake assays indicated that EV-GFP was more efficiently taken up than soluble GFP by mouse splenocytes and such uptake was B cell preferential. Taken together, our data indicate that viral TMs can efficiently load antigens onto the EV surface, and that EV-bound antigen enhances both humoral and cell-mediated antigen-specific responses.

Potent Virustatic Polymer-Lipid Nanomimics Block Viral Entry and Inhibit Malaria Parasites In Vivo.

Infectious diseases continue to pose a substantial burden on global populations, requiring innovative broad-spectrum prophylactic and treatment alternatives. Here, we have designed modular synthetic polymer nanoparticles that mimic functional components of host cell membranes, yielding multivalent nanomimics that act by directly binding to varied pathogens. Nanomimic blood circulation time was prolonged by reformulating polymer-lipid hybrids. Femtomolar concentrations of the polymer nanomimics were sufficient to inhibit herpes simplex virus type 2 (HSV-2) entry into epithelial cells, while higher doses were needed against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Given their observed virustatic mode of action, the nanomimics were also tested with malaria parasite blood-stage merozoites, which lose their invasive capacity after a few minutes. Efficient inhibition of merozoite invasion of red blood cells was demonstrated both in vitro and in vivo using a preclinical rodent malaria model. We envision these nanomimics forming an adaptable platform for developing pathogen entry inhibitors and as immunomodulators, wherein nanomimic-inhibited pathogens can be secondarily targeted to sites of immune recognition.

A Synthetic Carrier of Nucleic Acids Structured as a Neutral Phospholipid Envelope Tightly Assembled on Polyplex Surface.

Synthetic carriers of nucleic acids remain inefficient for practical applications due to their insufficient functions as compared with viral vectors developed by evolution. Here, a synthetic carrier is designed to structurally mimic lentivirus, a widely-used viral vector in therapeutic developments, for its neutral phospholipid membrane tightly anchored on the surface of a packed nucleic acid core. Unlike the reported lipopolyplexes of which the surface membrane around the nucleic acid core is formed from charged lipids, the stable attachment of the neutral lipids to each polyplex core in the present system is achieved through preadsorbed micelles of multicarboxyl amphiphilic molecules as lipid bilayer anchors. The adsorbed micelles are under a tension of deformation due to the electrostatic attraction of the head groups to the cationic surface and their "thermodynamic responsibility" to cover the hydrophobic tails in water. When liposomes of neutral phospholipids approach, the hydrophobic tail groups of the adsorbed micelles may insert into the lipid bilayer matrix to induce them to fuse around polyplex and relieve the thermodynamic tension. The formed neutral phospholipid membrane may encapsulate the polyplex core stably, prevent siRNA from prephagocytic leaking and degrading, and immobilize functional agents with increased capacity.

Neutrophils Enable Local and Non-Invasive Liposome Delivery to Inflamed Skeletal Muscle and Ischemic Heart.

Uncontrolled inflammation is a major pathological factor underlying a range of diseases including autoimmune conditions, cardiovascular disease, and cancer. Improving localized delivery of immunosuppressive drugs to inflamed tissue in a non-invasive manner offers significant promise to reduce severe side effects caused by systemic administration. Here, a neutrophil-mediated delivery system able to transport drug-loaded nanocarriers to inflamed tissue by exploiting the inherent ability of neutrophils to migrate to inflammatory tissue is reported. This hybrid system (neutrophils loaded with liposomes ex vivo) efficiently migrates in vitro following an inflammatory chemokine gradient. Furthermore, the triggered release of loaded liposomes and reuptake by target macrophages is studied. The migratory behavior of liposome-loaded neutrophils is confirmed in vivo by demonstrating the delivery of drug-loaded liposomes to an inflamed skeletal muscle in mice. A single low-dose injection of the hybrid system locally reduces inflammatory cytokine levels. Biodistribution of liposome-loaded neutrophils in a human-disease-relevant myocardial ischemia reperfusion injury mouse model after i.v. injection confirms the ability of injected neutrophils to carry loaded liposomes to inflammation sites. This strategy shows the potential of nanocarrier-loaded neutrophils as a universal platform to deliver anti-inflammatory drugs to promote tissue regeneration in inflammatory diseases.

Controlled Dendrimersome Nanoreactor System for Localized Hypochlorite-Induced Killing of Bacteria.

Antibiotic resistance is a serious global health problem necessitating new bactericidal approaches such as nanomedicines. Dendrimersomes (DSs) have recently become a valuable alternative nanocarrier to polymersomes and liposomes due to their molecular definition and synthetic versatility. Despite this, their biomedical application is still in its infancy. Inspired by the localized antimicrobial function of neutrophil phagosomes and the versatility of DSs, a simple three-component DS-based nanoreactor with broad-spectrum bactericidal activity is presented. This was achieved by encapsulation of glucose oxidase (GOX) and myeloperoxidase (MPO) within DSs (GOX-MPO-DSs), self-assembled from an amphiphilic Janus dendrimer, that possesses a semipermeable membrane. By external addition of glucose to GOX-MPO-DS, the production of hypochlorite (-OCl), a highly potent antimicrobial, by the enzymatic cascade was demonstrated. This cascade nanoreactor yielded a potent bactericidal effect against two important multidrug resistant pathogens, Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa), not observed for H2O2 producing nanoreactors, GOX-DS. The production of highly reactive species such as -OCl represents a harsh bactericidal approach that could also be cytotoxic to mammalian cells. This necessitates the development of strategies for activating -OCl production in a localized manner in response to a bacterial stimulus. One option of locally releasing sufficient amounts of substrate using a bacterial trigger (released toxins) was demonstrated with lipidic glucose-loaded giant unilamellar vesicles (GUVs), envisioning, e.g., implant surface modification with nanoreactors and GUVs for localized production of bactericidal agents in the presence of bacterial growth.

Tuneable peptide cross-linked nanogels for enzyme-triggered protein delivery.

Many diseases are associated with the dysregulated activity of enzymes, such as matrix metalloproteinases (MMPs). This dysregulation can be leveraged in drug delivery to achieve disease- or site-specific cargo release. Self-assembled polymeric nanoparticles are versatile drug carrier materials due to the accessible diversity of polymer chemistry. However, efficient loading of sensitive cargo, such as proteins, and introducing functional enzyme-responsive behaviour remain challenging. Herein, peptide-crosslinked, temperature-sensitive nanogels for protein delivery were designed to respond to MMP-7, which is overexpressed in many pathologies including cancer and inflammatory diseases. The incorporation of N-cyclopropylacrylamide (NCPAM) into N-isopropylacrylamide (NIPAM)-based copolymers enabled us to tune the polymer lower critical solution temperature from 33 to 44 °C, allowing the encapsulation of protein cargo and nanogel-crosslinking at slightly elevated temperatures. This approach resulted in nanogels that were held together by MMP-sensitive peptides for enzyme-specific protein delivery. We employed a combination of cryogenic transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), small angle neutron scattering (SANS), and fluorescence correlation spectroscopy (FCS) to precisely decipher the morphology, self-assembly mechanism, enzyme-responsiveness, and model protein loading/release properties of our nanogel platform. Simple variation of the peptide linker sequence and combining multiple different crosslinkers will enable us to adjust our platform to target specific diseases in the future.

The rotating stretched curved planar reconstruction of 3D-FIESTA MR imaging for evaluating the anterior cruciate ligament of the knee joint.

PURPOSE: To determine the feasibility of the rotating stretched curved planar reconstruction (CPR) of three-dimensional fast imaging with steady-state acquisition magnetic resonance imaging (3D-FIESTA MRI) for evaluating the anterior cruciate ligament of the knee joint. MATERIALS AND METHODS: MRI of 40 knee joints in healthy volunteers was performed on a 3.0-T MR scanner and a phased-array extremity coil. The protocol consisted of oblique sagittal spin echo (SE) T1WI, coronal FS-PDWI, axial FS-FSE-T2WI, and 3D-FIESTA sequences. The rotating stretched curved planar reconstructions (CPR) of the ACL at angles of 0°, 30°, 60°, 90°, 120°, 150°, and 180° were generated from images of 3D-FIESTA sequences. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the 3D-FIESTA were compared with those of the oblique sagittal SE T1WI sequence. The presence of the tibial attachment, midportion, femoral attachment, and double bundles of the ACL on the oblique sagittal SE T1WI and CPR of 3D-FIESTA MR imaging were divided into two categories: visible and not visible. RESULTS: The ACL SNR efficiency of 3D-FIESTA sequences was significantly higher than that of oblique sagittal SE T1WI sequence (P < 0.05). The 3D-FIESTA sequences produced images with a significantly higher CNR between ACL and synovial fluid than did the oblique sagittal SE T1WI sequence (P < 0.05). CPR of 3D-FIESTA MRI generated an excellent visualization of the ACL. The CPR of 3D-FIESTA MRI was rated superior to oblique sagittal SE T1WI sequence in 60% and 65% of cases with regard to the tibial attachment and midportion of ACL, respectively (P < 0.05). CPR of 3D-FIESTA MR imaging was rated superior to oblique sagittal SE T1WI sequence in 80% and 85% of cases with regard to femoral attachment and double bundles of ACL, respectively (P < 0.05). CONCLUSION: The rotating stretched curved planar reconstruction of 3D-FIESTA sequences is significantly better than that of conventional 2D-MRI in evaluating the native ACL and its components, AM bundle and PL bundle, in healthy volunteers.