Multifunctional nanoparticles with combined diagnostic and therapeutic functions show great promise towards personalized nanomedicine. However, attaining consistently high performance of these functions in vivo in one single nano-construct remains extremely challenging. Here we demonstrate the use of one single polymer to develop a smart “all-in-one” nanoporphyrin platform that conveniently integrates a broad range of clinically relevant functions. Nanoporphyrins can be used as amplifiable multimodality nanoprobes for near-infrared fluorescence imaging (NIRFI), magnetic resonance imaging (MRI), positron emission tomography (PET) and dual modal PET-MRI. Nanoporphyrins greatly increase the imaging sensitivity for tumor detection through background suppression in blood, as well as preferential accumulation and signal amplification in tumors. Nanoporphyrins also function as multiphase nanotransducers that can efficiently convert light to heat inside tumors for photothermal-therapy (PTT), and light to singlet oxygen for photodynamic-therapy (PDT). Furthermore, nanoporphyrins act as programmable releasing nanocarriers for targeted delivery of drugs into tumors.

Complementary imaging modalities provide more information than either method alone can yield and we have developed a dual-mode imaging probe for combined magnetic resonance (MR) and positron emission tomography (PET) imaging. We have developed dual-mode PET/MRI active probes targeted to vascular inflammation and present synthesis of (1) an aliphatic amine polystyrene bead and (2) a novel superparamagnetic iron oxide nanoparticle targeted to macrophages that were both coupled to positron-emitting copper-64 isotopes. The amine groups of the polystyrene beads were directly conjugated with an amine-reactive form (isothiocyanate) of aza-macrocycle 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid (DOTA). Iron oxide nanoparticles are dextran sulfate coated, and the surface was modified to contain aldehyde groups to conjugate to an amine-activated DOTA. Incorporation of chelated Cu-64 to nanoparticles under these conditions, which is routinely used to couple DOTA to macromolecules, was unexpectedly difficult and illustrates that traditional conjugation methods do not always work in a nanoparticle environment. Therefore, we developed new methods to couple Cu-64 to nanoparticles and demonstrate successful labeling to a range of nanoparticle types. We obtained labeling yields of 24% for the amine polystyrene beads and 21% radiolabeling yield for the anionic dextran sulfate iron oxide nanoparticles. The new coupling chemistry can be generalized for attaching chelated metals to other nanoparticle platforms.

Radiolabeling of liposomes with 64 Cu (t 1/2 = 12.7 h) is attractive for molecular imaging and monitoring drug delivery. A simple chelation procedure, performed at a low temperature and under mild conditions, is required to radiolabel pre-loaded liposomes without lipid hydrolysis or the release of the encapsulated contents. Here we report a 64 Cu post-labeling method for liposomes. A 64 Cuspecific chelator, 6-[p-(bromoacetamido)benzyl]-1,4,8,11-tetraazacyclotetradecane-N,N',N",N"'-tetraacetic acid (BAT), was conjugated with an artificial lipid to form a BAT-PEG-lipid. After incorporation of 0.5% (mol/mol) BAT-PEG-lipid during the liposome formulation, liposomes were successfully labeled with 64 Cu in 0.1 M NH 4 OAc pH 5 buffer, at 35 °C for 30~40 min with an incorporation yield as high as 95%. After 48 hour incubation of 64 Cu-liposomes in 50/50 serum/PBS solution, more than 88% of the 64 Cu label was still associated with liposomes. After injection of liposomal 64 Cu in a mouse model, 44 ± 6.9, 21 ± 2.7, 15 ± 2.5, and 7.4 ± 1.1 (n = 4) % of the injected dose per cubic centimeter remained within the blood pool at 30 min, 18, 28, and 48 hours, respectively. The biodistribution at 48 hours after injection verified that 7.0 ± 0.47 (n = 4), and 1.4 ± 0.58 (n = 3) % of the injected dose per gram of liposomal 64 Cu and free 64 Cu remained in the blood pool, respectively. Our results suggest that this fast and easy 64 Cu labeling of liposomes could be exploited in tracking liposomes in vivo for medical imaging and targeted delivery.

BackgroundAcute intoxication with organophosphorus (OP) cholinesterase inhibitors can trigger convulsions that progress to life-threatening status epilepticus. Survivors face long-term morbidity including mild-to-severe decline in memory. It is posited that neuroinflammation plays a key role in the pathogenesis of OP-induced neuropsychiatric deficits. Rigorous testing of this hypothesis requires preclinical models that recapitulate relevant phenotypic outcomes. Here, we describe a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) that exhibits persistent neuroinflammation and cognitive impairment.MethodsNeuroinflammation, neurodegeneration, and cognitive function were compared in adult male Sprague Dawley rats injected with an acutely toxic dose of DFP vs. vehicle controls at multiple time points up to 36 days post-exposure. Neuroinflammation was quantified using immunohistochemical biomarkers of microglia (ionized calcium-binding adapter molecule 1, IBA1) and activated astrocytes (glial fibrillary acidic protein, GFAP) and positron emission tomography (PET) imaging of [11C]-(R)-PK11195, a ligand for the 18-kDa mitochondrial membrane translocator protein (TSPO). FluoroJade-B staining was used to assess neurodegeneration; Pavlovian conditioning, to assess cognitive function.ResultsAnimals exhibited moderate-to-severe seizures within minutes of DFP injection that continued for up to 6 h post-injection. As indicated by IBA1 and GFAP immunoreactivity and by PET imaging of TSPO, acute DFP intoxication triggered neuroinflammation in the hippocampus and cortex during the first 3 days that peaked at 7 days and persisted to 21 days post-exposure in most animals. Neurodegeneration was detected in multiple brain regions from 1 to 14 days post-exposure. All DFP-intoxicated animals exhibited significant deficits in contextual fear conditioning at 9 and 20 days post-exposure compared to vehicle controls. Whole-brain TSPO labeling positively correlated with seizure severity score, but did not correlate with performance in the contextual fear-conditioning task.ConclusionsWe describe a preclinical model in which acute DFP intoxication causes seizures, persistent neuroinflammation, neurodegeneration, and memory impairment. The extent of the neuroinflammatory response is influenced by seizure severity. However, the observation that a subset of animals with moderate seizures and minimal TSPO labeling exhibited cognitive deficits comparable to those of animals with severe seizures and significant TSPO labeling suggests that DFP may impair learning and memory circuitry via mechanisms independent of seizures or neuroinflammation.

Synergistic multimodality therapy is needed for breast cancer. Breast cancer frequently has p53 mutations that result in cells less likely to undergo apoptosis when exposed to DNA damaging therapies. Taxol