Targeted care navigation to reduce hospital readmissions in 'at-risk' patients.

BACKGROUND: Care navigation is commonly used to reduce preventable hospitalisation. The use of Electronic Health Record-derived algorithms may enable better targeting of this intervention for greater impact. AIMS: To evaluate if community-based Targeted Care Navigation, supported by an Electronic Health Record-derived readmission risk algorithm, is associated with reduced rehospitalisation. METHODS: A propensity score matching cohort (5 comparison to 1 intervention cohort ratio) study was conducted in an 850-bed Victorian public metropolitan health service, Australia, from May to November 2017. Admitted acute care patients with a non-surgical condition, identified as at-risk of hospital readmission using an Electronic Health Record-derived readmission risk algorithm provide by the state health department, were eligible. Targeted Care Navigation involved telephone follow-up support provided for 30 days post-discharge by a registered nurse. The hazard ratio for hospital readmission was calculated at 30, 60 and 90 days post-discharge using multivariable Cox Proportional Hazards regression. RESULTS: Sixty-five recipients received care navigation and were matched to 262 people who did not receive care navigation. Excellent matching was achieved with standardised differences between groups being <0.1 for all 11 variables included in the propensity score, including the readmission risk score. The Targeted Care Navigation group had a significantly reduced hazard of readmission at 30 days (hazard ratio 0.34; 95% confidence interval: 0.12, 0.94) compared with the comparison group. The effect size was reduced at 60 and 90 days post-discharge. CONCLUSION: We provide preliminary evidence that Targeted Care Navigation supported by an Electronic Health Record-derived readmission risk algorithm may reduce 30-day hospital readmissions.

Screening for canine transitional cell carcinoma (TCC) by SERS-based quantitative urine cytology.

Canine lower urinary tract neoplasia is a clinically important disease process that has high mortality due to late stage diagnosis and poorly durable response to treatment. Non-invasive diagnostic techniques (e.g. dipstick test, urine cytology) currently have poor diagnostic value, while more invasive tests (e.g. cystoscopy and biopsy) are costly and often require general anesthesia. We have developed and herein describe a quantitative cytological analysis method based on the use of surface-enhanced Raman spectroscopy (SERS), for identifying cancerous transitional cells in urine using SERS biotags (SBTs) carrying the peptide PLZ4 (amino acid sequence cQDGRMGFc) that targets malignant transitional cells. By analyzing the ratio of the PLZ4-SBTs to an on board control we were able to show that transitional cells had significantly higher ratios (P < 0.05) in patients diagnosed with transitional cell carcinoma (TCC) than in healthy samples.

Nanostructured Antagonist of Extrasynaptic NMDA Receptors.

Glutamatergic cytotoxicity mediated by overactivation of N-methyl-d-aspartate receptors (NMDARs) is implicated in numerous neurological disorders. To be therapeutically viable, NMDAR antagonists must preserve physiological role of synaptic NMDARs (sNMDARs) in synaptic transmission and block only excessive pathological activation of NMDARs. Here we present a novel NMDAR antagonist that satisfies this two-fold requirement by exploiting spatial differences in NMDAR subcellular locations. Specifically, we designed a hybrid nanodrug (AuM) to be larger than the synaptic cleft by attaching memantine, NMDAR antagonist, via polymer linkers to a gold nanoparticle. We show that AuM efficiently and selectively inhibited extrasynaptic NMDARs (eNMDARs), while having no effect on sNMDARs and synaptic transmission. AuM exhibited neuroprotective properties both in vitro and ex vivo during such neurotoxic insults as NMDAR-mediated cytotoxicity in cerebrocortical cell culture and oxygen-glucose deprivation in acute hippocampal slices. Furthermore, AuM prevented dendritic spine loss triggered by Aß oligomers in organotypic hippocampal slices and was more effective than free memantine. Using a novel rational design strategy, we demonstrate a proof of concept for a new class of neuroprotective drugs that might be beneficial for treatment of several neurological disorders.

Tumor-Targeted Multimodal Optical Imaging with Versatile Cadmium-Free Quantum Dots.

The rapid development of fluorescence imaging technologies requires concurrent improvements in the performance of fluorescent probes. Quantum dots have been extensively used as an imaging probe in various research areas because of their inherent advantages based on unique optical and electronic properties. However, their clinical translation has been limited by the potential toxicity especially from cadmium. Here, a versatile bioimaging probe is developed by using highly luminescent cadmium-free CuInSe2/ZnS core/shell quantum dots conjugated with CGKRK (Cys-Gly-Lys-Arg-Lys) tumor-targeting peptides. This probe exhibits excellent photostability, reasonably long circulation time, minimal toxicity, and strong tumor-specific homing property. The most important feature of this probe is that it shows distinctive versatility in tumor-targeted multimodal imaging including near-infrared, time-gated, and two-photon imaging in different tumor models. In a glioblastoma mouse model, the targeted probe clearly denotes tumor boundaries and positively labels a population of diffusely infiltrating tumor cells, suggesting its utility in precise tumor detection during surgery. This work lays a foundation for potential clinical translation of the probe.

New p32/gC1qR Ligands for Targeted Tumor Drug Delivery.

Cell surface p32, the target of LyP-1 homing peptide, is upregulated in tumors and atherosclerotic plaques and has been widely used as a receptor for systemic delivery of payloads. Here, we identified an improved LyP-1-mimicking peptide (TT1, CKRGARSTC). We used this peptide in a fluorescence polarization-based high-throughput screening of a 50,000-compound chemical library and identified a panel of compounds that bind p32 with low micromolar affinity. Among the hits identified in the screen, two compounds were shown to specifically bind to p32 in multiple assays. One of these compounds was chosen for an in vivo study. Nanoparticles surface-functionalized with this compound specifically adhered to surfaces coated with recombinant p32 and, when injected intravenously, homed to p32-expressing breast tumors in mice. This compound provides a lead for the development of p32-targeted affinity ligands that circumvent some of the limitations of peptide-based probes in guided drug delivery.

Biotags Based on Surface-Enhanced Raman Can Be as Bright as Fluorescence Tags.

Surface enhanced Raman spectroscopy (SERS) is a powerful analytical technique that has been proposed as a substitute for fluorescence for biological imaging and detection but is not yet commercially utilized. The reason lies primarily in the lower intensity and poor reproducibility of most metal nanoparticle-based tags as compared to their fluorescence-based counterparts. Here, using a technique that scrupulously preserves the same number of dye molecules in both the SERS and fluorescence measurements, we show that SERS-based biotags (SBTs) with highly reproducible optical properties can be nanoengineered such that their brightness is at least equal to that of fluorescence-based tags.

Advances in superresolution optical fluctuation imaging (SOFI).

We review the concept of superresolution optical fluctuation imaging (SOFI), discuss its attributes and trade-offs (in comparison with other superresolution methods), and present superresolved images taken on samples stained with quantum dots, organic dyes, and plasmonic metal nanoparticles. We also discuss the prospects of SOFI for live cell superresolution imaging and for imaging with other (non-fluorescent) contrasts.

Etchable plasmonic nanoparticle probes to image and quantify cellular internalization.

There is considerable interest in using nanoparticles as labels or to deliver drugs and other bioactive compounds to cells in vitro and in vivo. Fluorescent imaging, commonly used to study internalization and subcellular localization of nanoparticles, does not allow unequivocal distinction between cell surface-bound and internalized particles, as there is no methodology to turn particles 'off'. We have developed a simple technique to rapidly remove silver nanoparticles outside living cells, leaving only the internalized pool for imaging or quantification. The silver nanoparticle (AgNP) etching is based on the sensitivity of Ag to a hexacyanoferrate-thiosulphate redox-based destain solution. In demonstration of the technique we present a class of multicoloured plasmonic nanoprobes comprising dye-labelled AgNPs that are exceptionally bright and photostable, carry peptides as model targeting ligands, can be etched rapidly and with minimal toxicity in mice, and that show tumour uptake in vivo.

Targeted intracellular delivery of proteins with spatial and temporal control.

While a host of methods exist to deliver genetic materials or small molecules to cells, very few are available for protein delivery to the cytosol. We describe a modular, light-activated nanocarrier that transports proteins into cells by receptor-mediated endocytosis and delivers the cargo to the cytosol by light triggered endosomal escape. The platform is based on hollow gold nanoshells (HGN) with polyhistidine tagged proteins attached through an avidity-enhanced, nickel chelation linking layer; here, we used green fluorescent protein (GFP) as a model deliverable cargo. Endosomal uptake of the GFP loaded nanocarrier was mediated by a C-end Rule (CendR) internalizing peptide fused to the GFP. Focused femtosecond pulsed-laser excitation triggered protein release from the nanocarrier and endosome disruption, and the released protein was capable of targeting the nucleoli, a model intracellular organelle. We further demonstrate the generality of the approach by loading and releasing Sox2 and p53. This method for targeting of individual cells, with resolution similar to microinjection, provides spatial and temporal control over protein delivery.

Modular plasmonic nanocarriers for efficient and targeted delivery of cancer-therapeutic siRNA.

We have combined a versatile and powerful route to deliver nucleic acids with peptide-based cell-specific targeting. siRNA targeting the polo-like kinase gene is in clinical trials for cancer treatment, and here we deliver this RNA selectively to cancer cells displaying the neuropilin-1 epitope using gold nanoshells. Release of the siRNA from the nanoparticles results from irradiation with a pulsed near-infrared laser, which also provides efficient endosomal escape within the cell. As a result, our approach requires 10-fold less material than standard nucleic acid transduction materials and is significantly more efficient than other particle-based methods. We also describe a particle-nucleic acid design that does not rely on modified RNA, thereby making the preparation of these materials more efficient and much less expensive. These improvements, when combined with control over when and where the siRNA is released, could provide the basis for diverse cell biological studies.

Clotting activity of polyphosphate-functionalized silica nanoparticles.

We present a silica nanoparticle (SNP) functionalized with polyphosphate (polyP) that accelerates the natural clotting process of the body. SNPs initiate the contact pathway of the blood-clotting system; short-chain polyP accelerates the common pathway by the rapid formation of thrombin, which enhances the overall blood-clotting system, both by accelerating fibrin generation and by facilitating the regulatory anticoagulation mechanisms essential for hemostasis. Analysis of the clotting properties of bare SNPs, bare polyP, and polyP-functionalized SNPs in plasma demonstrated that the attachment of polyP to SNPs to form polyP-SNPs creates a substantially enhanced synergistic effect that lowers clotting time and increases thrombin production at low concentrations. PolyP-SNP even retains its clotting function at ambient temperature. The polyP-SNP system has the potential to significantly improve trauma-treatment protocols and outcomes in hospital and prehospital settings.

Quantitative ratiometric discrimination between noncancerous and cancerous prostate cells based on neuropilin-1 overexpression.

A multiplexed, ratiometric method is described that can confidently distinguish between cancerous and noncancerous epithelial prostate cells in vitro. The technique is based on bright surface-enhanced resonance Raman scattering (SERRS) biotags (SBTs) infused with unique Raman reporter molecules, and carrying cell-specific peptides. Two sets of SBTs were used. One targets the neuropilin-1 (NRP-1) receptors of cancer cells through the RPARPAR peptide. The other functions as a positive control (PC) and binds to both noncancerous and cancer cells through the HIV-derived TAT peptide. Point-by-point 2D Raman maps of the spatial distribution of the two tags were constructed with subcellular resolution from cells simultaneously incubated with the two sets of SBTs. Averaging the SERRS signal over a given cell yielded an NRP/PC ratio from which a robust quantitative measure of the overexpression of the NRP-1 by the cancer cell line was extracted. The use of a local, on-cell reference produces quantitative, statistically robust measures of overexpression independent of such sources of uncertainty as variations in the location of the focal plane, the local cell concentration, and turbidity.

Robust SERS enhancement factor statistics using rotational correlation spectroscopy.

We characterize the distribution of surface-enhanced Raman spectroscopy (SERS) enhancement factors observed in individual hot spots of single Ag "nanocapsules", encapsulated Ag nanoparticle dimers formed via controlled nanoparticle linking, polymer encapsulation, and small molecule infusion. The enhancement factors are calculated for over 1000 individual nanocapsules by comparing Raman scattering intensities of 4-mercaptobenzoic acid (MBA) measured from single SERS hot spots to intensities measured from high-concentration solutions of MBA. Correlation spectroscopy measurements of the rotational diffusion identify nanocapsules with signals dominated by single hot spots via their strong polarization response. Averaging over the entire surface of the nanocapsules, the distribution of enhancement factors is found to range from 10(6) to 10(8), with a mean of 6 × 10(6). Averaging only over nanoparticle junctions (where most SERS signals are expected) increases this average value to 10(8), with a range from 2 × 10(7) to 2 × 10(9). This significant statistical sampling shows that very high SERS enhancement factors can be obtained on a consistent basis using nanoparticle linking.

Mesoporous multifunctional upconversion luminescent and magnetic "nanorattle" materials for targeted chemotherapy.

Nanorattles consisting of hydrophilic, rare-earth-doped NaYF(4) shells each containing a loose magnetic nanoparticle were fabricated through an ion-exchange process. The inner magnetic Fe(3)O(4) nanoparticles are coated with a SiO(2) layer to avoid iron leaching in acidic biological environments. This multifunctional mesoporous nanostructure with both upconversion luminescent and magnetic properties has excellent water dispersibility and a high drug-loading capacity. The material emits visible luminescence upon NIR excitation and can be directed by an external magnetic field to a specific target, making it an attractive system for a variety of biological applications. Measurements on cells incubated with the nanorattles show them to have low cytotoxicity and excellent cell imaging properties. In vivo experiments yield highly encouraging tumor shrinkage with the antitumor drug doxorubicin (DOX) and significantly enhanced tumor targeting in the presence of an applied magnetic field.

Impact of COVID-19 lockdowns on hospital presentations and admissions in the context of low community transmission: evidence from time series analysis in Melbourne, Australia.

BACKGROUND: Melbourne, Australia, successfully halted exponential transmission of COVID-19 via two strict lockdowns during 2020. The impact of such restrictions on healthcare-seeking behaviour is not comprehensively understood, but is of global importance. We explore the impact of the COVID-19 pandemic on acute, subacute and emergency department (ED) presentations/admissions within a tertiary, metropolitan health service in Melbourne, Australia, over two waves of community transmission (1 March to 20 September 2020). METHODS: We used 4 years of historical data and novel forecasting methods to predict counterfactual hospital activity for 2020, assuming absence of COVID-19. Observed activity was compared with forecasts overall, by age, triage category and for myocardial infarction and stroke. Data were analysed for all patients residing in the health service catchment area presenting between 4 January 2016 and 20 September 2020. RESULTS: ED presentations (n=401 805), acute admissions (n=371 723) and subacute admissions (n=15 676) were analysed. Substantial departures from forecasted presentation levels were observed during both waves in the ED and acute settings, and during the second wave in subacute. Reductions were most marked among those aged >80 and <18 years. Presentations persisted at expected levels for urgent conditions, and ED triage categories 1 and 5, with clear reductions in categories 2-4. CONCLUSIONS: Our analyses suggest citizens were willing and able to present with life-threatening conditions during Melbourne's lockdowns, and that switching to telemedicine did not cause widespread spill-over from primary care into ED. During a pandemic, lockdowns may not inhibit appropriate hospital attendance where rates of infectious disease are low.

Novel Methods of Enhanced Retention in and Rapid, Targeted Release from Liposomes.

Liposomes are single bilayer capsules with distinct interior compartments in which hydrophilic drugs, imaging agents, diagnostics, etc. can be sequestered from the exterior environment. The polar parts of the individual lipids face the water compartments, while the hydrophobic parts of the lipid provide a barrier in which hydrophilic or charged molecules are poorly soluble. Hydrophobic molecules can be dissolved within the bilayer. The bilayers are typically from 3 - 6 nm thick and the liposome can range from about 50 nm - 50 microns in diameter. The question asked in this review is if any one bilayer, regardless of its composition, can provide the extended drug retention, long lifetime in the circulation, active targeting to specific tissues and rapid and controllable drug release at the site of interest. As an alternative, we review methods of self-assembling multicompartment lipid structures that provide enhanced drug retention in physiological environments. We also review methods of externally targeting and triggering drug release via the near infrared heating of gold nanoshells attached to or encapsulated within bilayer vesicles.

Single-order, subwavelength resonant nanograting as a uniformly hot substrate for surface-enhanced Raman spectroscopy.

The surface-enhanced Raman spectroscopy (SERS) activity and the optical reflectance of a subwavelength gold nanograting fabricated entirely using top down technologies on silicon wafers are presented. The grating consists of 120 nm gold cladding on top of parallel silica nanowires constituting the grating's lines, with gaps between nanowires <10 nm wide at their narrowest point. The grating produces inordinately intense SERS and shows very strong polarization dependence. Reflectance measurements for the optimized grating indicate that (when p-polarization is used and at least one of the incident electric field components lies across the grating lines) the reflectance drops to <1% at resonance, indicating that essentially all of the radiant energy falling on the surface is coupled into the grating. The SERS intensity and the reflectance at resonance anticorrelate predicatively, suggesting that reflectance measurements can provide a nondestructive, wafer-level test of SERS efficacy. The SERS performance of the gratings is very uniform and reproducible. Extensive measurements on samples cut from both the same wafer and from different wafers, produce a SERS intensity distribution function that is similar to that obtained for ordinary Raman measurements carried out at multiple locations on a polished (100) silicon wafer.

Tumor-penetrating therapy for ß5 integrin-rich pancreas cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by marked desmoplasia and drug resistance due, in part, to poor drug delivery to extravascular tumor tissue. Here, we report that carcinoma-associated fibroblasts (CAFs) induce ß5 integrin expression in tumor cells in a TGF-ß dependent manner, making them an efficient drug delivery target for the tumor-penetrating peptide iRGD. The capacity of iRGD to deliver conjugated and co-injected payloads is markedly suppressed when ß5 integrins are knocked out in the tumor cells. Of note, ß5 integrin knock-out in tumor cells leads to reduced disease burden and prolonged survival of the mice, demonstrating its contribution to PDAC progression. iRGD significantly potentiates co-injected chemotherapy in KPC mice with high ß5 integrin expression and may be a powerful strategy to target an aggressive PDAC subpopulation.

Fabrication of Ag@SiO(2)@Y(2)O(3):Er nanostructures for bioimaging: tuning of the upconversion fluorescence with silver nanoparticles.

We demonstrated that the nanostructures comprising silver cores and dense layers of Y(2)O(3):Er separated by a silica shell are an excellent model system to study the interaction between upconversion materials and metals in nanoscale. This architecture allows for versatile control of the Y(2)O(3):Er-metal interaction through control of the silica dielectric spacer thickness and the metal-core size. Finally, the nanoparticles are potentially interesting as fluorescent labels in, for instance (single particle), imaging experiments or bioassays which require low background or tissue penetrating wavelengths.

Cell-targeted self-assembled DNA nanostructures.

We present two strategies for attaching self-assembled DNA arrays to the surfaces of cells. Our first approach uses biotin-streptavidin interactions to bind DNA architectures to biotinylated cells. The second approach takes advantage of specific antibody-cell surface interactions, conjugated arrays and the subsequent binding to native epidermal growth factor receptors expressed on cancer cells. DNA array-cell surface interactions were visualized by fluorescence, confocal microscopy, and scanning electron microscopy. This novel application of DNA nanoarrays provides strategies to specifically label cell surfaces with micrometer-sized patches, bind cells onto a designed functionalized DNA scaffold, engineer cell/cell networks into microtissues, and deliver materials to cell surfaces.