We present a method to map fluorescence resonance energy transfer (FRET) parameters of a bifunctional photodynamic therapy agent, (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a)-cyanine dye (HPPH-CD) conjugate, which consists of a photosensitizer (HPPH) and a fluorescent agent CD. We utilized time-domain fluorescence diffuse optical tomography, the normalized Born ratio model in the Fourier-domain, and an iterative algorithm to map depth-resolved spatial heterogeneities of FRET parameters. Our results exhibited depth-resolved changes of fluorophore's lifetime and the distance maps due to FRET between HPPH and CD. Our model suggests a potential approach of using FRET parameters to monitor efficacies of multifunctional photodynamic therapy agents in deep tissue.

The tetrapyrrole structure of porphyrins used as photosentizing agents is thought to determine uptake and retention by malignant epithelial cancer cells. To assess the contribution of the oxidized state of individual rings to these cellular processes, bacteriochlorophyll a was converted into the ring "D" reduced 3-devinyl-3-[1-(1-hexyloxy)ethyl]pyropheophorbide-a (HPPH) and the corresponding ring "B" reduced isomer (iso-HPPH). The carboxylic acid analogs of both ring "B" and ring "D" reduced isomers showed several-fold higher accumulation into the mitochondria and endoplasmic reticulum by primary culture of human lung and head and neck cancer cells than the corresponding methyl ester analogs that localize primarily to granular vesicles and to a lesser extent to mitochondria. However, long-term cellular retention of these compounds exhibited an inverse relationship with tumor cells generally retaining better the methyl-ester derivatives. In vivo distribution and tumor uptake was evaluated in the isogenic model of BALB/c mice bearing Colon26 tumors using the respective 14C-labeled analogs. Both carboxylic acid derivatives demonstrated similar intracellular localization and long-term tumor cure with no significant skin phototoxicity. PDT-mediated tumor action involved vascular damage, which was confirmed by a reduction in blood flow and immunohistochemical assessment of damage to the vascular endothelium. The HPPH stereoisomers (epimers) showed identical uptake (in vitro & in vivo), intracellular retention and photoreaction.

Herein we report the synthesis of new gold nanoparticle-bacteriochlorin conjugate (Au-NP-PS) as a highly efficient photoacoustic (PA) imaging agent. The conjugate was obtained by reacting a water soluble thio-bacteriochlorin (derived from bacteriochlorophyll-[Formula: see text] with Au-NP. The resulting NPs were characterized by UV-vis, TEM (transmission electron microscopy)/HRTEM (high resolution TEM) and diffraction pattern. The results obtained from in vitro studies suggest that due to conjugation between the PS and Au-NPs, the photoacoustic (PA) signals from the Au-NP-PS were greatly enhanced by a factor of 2.4 compared to that from PS alone.

Herein we report the syntheses and comparative photophysical, electrochemical, in vitro, and in vivo biological efficacy of 3-(1'-hexyloxy)ethyl-3-devinylpyropheophorbide-cyanine dye (HPPH-CD) and the corresponding indium (In), gallium (Ga), and palladium (Pd) conjugates. The insertion of a heavy metal in the HPPH moiety makes a significant difference in FRET (Forster resonance energy transfer) and electrochemical properties, which correlates with singlet oxygen production [a key cytotoxic agent for photodynamic therapy (PDT)] and long-term in vivo PDT efficacy. Among the metalated analogs, the In(III) HPPH-CD showed the best cancer imaging and PDT efficacy. Interestingly, in contrast to free base HPPH-CD, which requires a significantly higher therapeutic dose (2.5 ymol/kg) than imaging dose (0.3 ymol/kg), the corresponding In(III) HPPH-CD showed excellent imaging and therapeutic potential at a remarkably low dose (0.3 itmol/kg) in BALB/c mice bearing Colon26 tumors. A comparative study of metalated and corresponding nonmetalated conjugates further confirmed that STAT-3 dimerization can be used as a biomarker for determining the level of photoreaction and tumor response.

To investigate the impact of linker(s) joining the photosensitizer HPPH [3-(1'-hexyloxy) ethyl-3-devinylpyropheophorbide-a] and the cyanine dye (CD) in tumor-imaging and photodynamic therapy (dual-function agents), a series of HPPH-CD conjugates were synthesized. The modifications were done in an attempt to minimize Forster Resonance Energy Transfer (FRET) between the two chromophores and maximize singlet oxygen production. Among the conjugates containing variable length of linkers, the HPPH-CD conjugate, in which the photosensitizer (PS) and the CD was joined by four Carbon [(CH2)4] units showed higher tumor uptake, improved tumor contrast and limited skin uptake in mice bearing Colon-26 (BALB/c) or U87 tumors in Nude mice. The bi-functional agents in which the HPPH was linked at the meta-position of phenyl-substituted CD 5, 6 and 7 showed longer tumor response (cure) than the corresponding para-substituted analogs 2, 3, and 4, which suggests that the orientation of the PS and CD moieties within the conjugate also makes a substantial difference in tumor-specificity. Compared to HPPH, the singlet oxygen yields of all the HPPH-CD conjugates were significantly low, and required a higher therapeutic dose to achieve the same in vivo response obtained by HPPH-PDT alone. However, conjugate 6 produced a higher singlet oxygen yield with reduced FRET and exhibited enhanced long-term PDT efficacy in mice bearing Colon-26 (BALB/c) and U87 tumors (nude) than its counterparts, including our lead compound (HPPH-CD), making it the most efficacious of the series. Thus, these conjugates bearing cyanine dye moiety (CD) provide an opportunity of imaging deeply seated tumors for fluorescence-guided surgery with an option of PDT.

Breast cancer is subdivided into three types: hormone (estrogen and progesterone) receptor (ER and PR) positive, Her2-neu positive and triple negative breast cancers. In general, surgical and radiation treatments are similar, but drug treatment for different subtypes of breast cancers is different. Endocrine therapy (ET) is specifically used for the treatment of ER and PR positive breast cancers. This review discusses every aspect of endocrine therapy: ovarian suppression agents, selective estrogen receptor modulators (SERMs) and downregulators, and aromatase inhibitors (AIs). The most famous agents for the treatment of HER2 positive breast cancers are trastuzumab and its derivative Kadcyla (ado-trastuzumabemtansine). Other agents for the treatment of this subtype of breast cancers are also discussed. For the treatment of triple-negative breast cancers (TNBC) and other breast cancers, the following agents are discussed: anthracyclines and related regimens, taxanes, combination therapy of platinum with taxanes, combination therapy to counter drug resistance, ixabepilone and other epothilones, angiogenesis inhibitors. The lack of known specific molecular targets has promoted abundant research in order to find possible "vulnerabilities" in TNBC. For the first time, we propose thetranslocator protein (TSPO) 18 kDa as a potential target for TNBC. Furthermore, currently Photodynamic Therapy (PDT) is way under-explored for the treatment of breast cancers. In this review, PDT for the treatment of breast cancers is discussed. We also discuss imaging-guided therapy for breast cancers. Finally, from a perspective point of view, we call on the development of more potent agents for differentiation therapy.

In this report we demonstrate the outstanding advantages of multifunctional nanoplatforms for cancer-imaging and therapy.The non-toxic polyacrylamide (PAA) nanoparticles (size:18-25 nm) formulation drastically changed the pharmacokinetic profile of the 124 I-labeled chlorophyll-a derivative (formulated in 10% ethanol in PBS) with a remarkable enhancement in tumor uptake, and significantly reduced uptake in spleen and liver.Among the various nanoformulations investigated, the 124 I-labeled photosensitizer (dose: 0.6142 MBq), and the cyanine dye-nanoparticles (CD-NP) conjugate (dose 0.3 μmol/kg) in combination showed great potential for tumor imaging (PET/NIR fluorescence) in BALB/c mice bearing Colon26 tumors.Compared to free non-labeled photosensitizer, the corresponding PAA nanoformulation under similar treatment parameters showed a remarkable enhancement in long-term tumor cure by PDT (photodynamic therapy) and provides an opportunity to develop a single nanoplatform for tumor-imaging (PET/fluorescence) and phototherapy, a practical "See and Treat" approach.

Previous reports from our laboratory have shown that a bifunctional agent obtained by conjugating a photosensitizer (HPPH) to a cyanine dye (CD) can be used for fluorescence image-guided treatment of tumor by photodynamic therapy (PDT).However, the resulting HPPH-CD conjugate showed a significant difference between the tumor-imaging and therapeutic doses.It was demonstrated that the singlet oxygen ( 1 O 2 * , a key cytotoxic agent in PDT) produced by the conjugate upon excitation of the HPPH moiety was partially quenched by the CD-moiety; this resulted in a reduced PDT response when compared to HPPH-PDT under similar treatment parameters.To improve the therapeutic potential of the conjugate, we synthesized a series of dual functional agents in which one or two HPPH moieties were separately conjugated to three different dyes (Cypate, modified IR820 or modified IR783).The newly synthesized conjugates were compared with our lead compound HPPH-CD in terms of photophysical properties, in vitro and in vivo PDT efficacy, tumor uptake and imaging potential.Among the analogs investigated, the conjugate, in which two HPPH moieties were linked to the modified IR820 produced enhanced tumor uptake and tumor contrast in both Colon 26 (a murine Colon carcinoma) and U87 (a human glioblastoma) cell lines.The long-term PDT efficacy (cure) of this conjugate in BALB/c mice, bearing Colon 26 tumors was also enhanced; however, its efficacy in Nude mice bearing U87 tumors was slightly reduced.It was also found that in all the conjugates the singlet oxygen generation and, consequently, PDT efficacy were compromised by a competing pathway, whereby an electronic excitation of HPPH, the energy donor, is deactivated through an electronic excitation energy transfer (Forster Resonance Energy Transfer, FRET) to the CD fluorophore, the energy acceptor, resulting in overall reduction of the singlet oxygen production.Conjugates with increased FRET showed reduced singlet oxygen production and PDT efficacy.Among the conjugates investigated, the bifunctional agent in which two HPPH moieties were linked to the benzoindole-based cyanine dye 11 showed superiority over the lead candidate 9 (mono HPPH-cyanine dye).

Near-infrared (NIR) organic dyes have become important for many biomedical applications, including in vivo optical imaging. Conjugation of NIR fluorescent dyes to photosensitizing molecules (photosensitizers) holds strong potential for NIR fluorescence image guided photodynamic therapy (PDT) of cancer. Therefore, we were interested in investigating the photophysical properties, in vivo tumor-affinity and fluorescence imaging potential of a series of heterocyclic polymethine dyes, which could then be conjugated to certain PDT agents. For our present study, we selected a series of symmetrical polymethine dyes containing a variety of bis-N-substituted indole or benzindole moieties linked by linear conjugation with and without a fused substituted cyclohexene ring. The N-alkyl side chain at the C-terminal position was functionalized with sulfonic, carboxylic acid, methyl ester or hydroxyl groups. Although, among the parent cyanine dyes investigated, the commercially available, cyanine dye IR783 (3) (bis-indole-N-butylsulfonate)-polymethine dye with a cyclic chloro-cyclohexene moiety showed best fluorescence-imaging ability, based on its spectral properties (λAbs=782 nm, λFl=810 nm, ε = 261,000 M-1cm-1, ΦFl≈0.08) and tumor affinity. In addition to 3, parent dyes IR820 and Cypate (6) were also selected and subjected to further modifications by introducing desired functional groups, which could enable further conjugation of the cyanine dyes to an effective photosensitizer HPPH developed in our laboratory. The synthesis and biological studies (tumor-imaging and PDT) of the resulting bifunctional conjugates are discussed in succeeding paper (Part-2 of this study).

Translocator protein (TSPO) 18 kDa overexpression has been observed in a large variety of human cancers, especially breast cancers. PK 11195, an isoquinoline analogue, is one of the ligands of highest TSPO binding affinity. Due to the long biological half life of our photosensitizers, there is a need to label them with a long lived radioisotope, for example I-124. Our objectives are to find translocator protein targeted photosensitizers for both tumor imaging (PET) and photodynamic therapy (PDT). I-PK 11195 is conjugated with the tumor avid photosensitizer HPPH. We find that those two tumor avid components complement each other and make the conjugate molecule even more tumor avid; compared to the photosensitizer itself, the conjugate is found to show improved PDT efficacy. It is concluded that I-PK 11195 can be a good vehicle to deliver radionuclide and photosensitizer to TSPO overexpressed tumor regions. Such conjugates could be useful for both tumor imaging (PET) and PDT.

Consider the recovery of the weight function in distributed time-fractional diffusion system using the interior measurement, which arises in some ultra-slow diffusion phenomena. Due to the nonlinear and nonlocal dependance of the measurement data on the weight function, such an inverse problem is novel and important. Based on the regularities of the direct problems for general diffusion equations with distributed time fractional derivative shown in this paper, we establish the theoretical framework for the optimization version of the inverse problem, including existence of the minimizer, the differentiability of the cost functional, as well as the gradient of the cost functional, in suitable functional spaces. Then an iteration process of descent type is realized efficiently for minimizing the regularizing cost functional in terms of the gradient type iteration, with numerical examples showing the validity of the proposed scheme.

Two types of polysilicon nanoparticles (PN) were used in oil fields to improve oil recovery and enhance water injection respectively in this work. The physical properties of the nanoparticles were studied experimentally, and pore characteristics of sandstone were investigated by mercury injection experiments. The adsorption experiments of lipophobic and hydrophilic polysilicon nanoparticles (LHPN) were conducted to testify wettability change (from oil wetting to water wetting) of sandstone surface, and the nanoparticles attached to pore walls were observed by a transmission electron microscope (TEM). A mathematical model to describe the nanoparticles transport carried by two-phase flow in random porous media was presented and a numerical simulator was developed to simulate two application examples of the nanoparticles in oilfields. An important discovery is that water-phase permeabilities of these sandstones increase from 1.6 to 2.1 times of their original values. However, there are decreases in their absolute permeabilities because of nanoparticle adsorption on pore surfaces and nanoparticle capture at pore throats. The important parameters such as the distributions of porosities and permeabilities, the changes in water injection capability and oil recovery are obtained successfully by numerical simulation approach. Furthermore, the permeabilities obtained from numerical simulation have a good match with experimental data. The conclusion that polysilicon nanoparticles are effective agents for enhancing water injection capability or improving oil recovery can be safely drawn.

In recent years several review articles and books have been published on the use of porphyrin-based compounds in photodynamic therapy (PDT). This critical review is focused on (i) the basic concept of PDT, (ii) advantages of long-wavelength absorbing photosensitizers (PS), (iii) a brief discussion on recent advances in developing PDT agents, and (iv) the various synthetic strategies designed at the Roswell Park Cancer Institute, Buffalo, for developing highly effective long-wavelength PDT agents and their utility in constructing the conjugates with tumor-imaging and therapeutic potential (Theranostics). The clinical status of certain selected PDT agents is also summarized (205 references).

In recent years several review articles and books have been published on the use of porphyrin-based compounds in photodynamic therapy (PDT). This critical review is focused on (i) the basic concept of PDT, (ii) advantages of long-wavelength absorbing photosensitizers (PS), (iii) a brief discussion on recent advances in developing PDT agents, and (iv) the various synthetic strategies designed at the Roswell Park Cancer Institute, Buffalo, for developing highly effective long-wavelength PDT agents and their utility in constructing the conjugates with tumor-imaging and therapeutic potential (Theranostics). The clinical status of certain selected PDT agents is also summarized (205 references).

Among the photosensitizers investigated, both ring-D and ring-B reduced chlorins containing the m-iodobenzyloxyethyl group at position-3 and a carboxylic acid functionality at position-17(2) showed the highest uptake by tumor cells and light-dependent photoreaction that correlated with maximal tumor-imaging [positron emission tomography (PET) and fluorescence] and long-term photodynamic therapy (PDT) efficacy in BALB/c mice bearing Colon26 tumors. However, among the ring-D reduced compounds, the isomer containing the 1'-m-iobenzyloxyethyl group at position-3 was more effective than the corresponding 8-(1'-m-iodobenzyloxyethyl) derivative. All photosensitizers showed maximum uptake by tumor tissue 24 h after injection, and the tumors exposed with light at low fluence and fluence rates (128 J/cm(2), 14 mW/cm(2)) produced significantly enhanced tumor eradication than those exposed at higher fluence and fluence rate (135 J/cm(2), 75 mW/cm(2)). Interestingly, dose-dependent cellular uptake of the compounds and light-dependent STAT3 dimerization have emerged as sensitive rapid indicators for PDT efficacy in vitro and in vivo and could be used as in vitro/in vivo biomarkers for evaluating and optimizing the in vivo treatment parameters of the existing and new PDT candidates.

To develop novel bifunctional agents for tumor imaging (MR) and photodynamic therapy (PDT), certain tumor-avid photosensitizers derived from chlorophyll-a were conjugated with variable number of Gd(III)aminobenzyl DTPA moieties. All the conjugates containing three or six gadolinium units showed significant T(1) and T(2) relaxivities. However, as a bifunctional agent, the 3-(1'-hexyloxyethyl)pyropheophorbide-a (HPPH) containing 3Gd(III) aminophenyl DTPA was most promising with possible applications in tumor-imaging and PDT. Compared to HPPH, the corresponding 3- and 6Gd(III)aminobenzyl DTPA conjugates exhibited similar electronic absorption characteristics with a slightly decreased intensity of the absorption band at 660 nm. However, compared to HPPH, the excitation of the broad "Soret" band (near 400 nm) of the corresponding 3Gd(III)aminobenzyl-DTPA analogues showed a significant decrease in the fluorescence intensity at 667 nm.

Conjugates of 3-(1'-hexyloxyethyl)-3-devinyl pyropheophorbide-a (HPPH) with multiple Gd(III)aminobenzyl diethylenetriamine pentacetic acid (ADTPA) moieties were evaluated for tumor imaging and photodynamic therapy (PDT). In vivo studies performed in both mice and rat tumor models resulted in a significant MR signal enhancement of tumors relative to surrounding tissues at 24 h postinjection. The water-soluble (pH: 7.4) HPPH-3Gd(III) ADTPA conjugate demonstrated high potential for tumor imaging by MR and fluorescence. This agent also produced long-term tumor cures via PDT. An in vivo biodistribution study with the corresponding (14)C-analogue also showed significant tumor uptake 24 h postinjection. Toxicological evaluations of HPHH-3Gd(III)ADTPA administered at and above imaging/therapeutic doses did not show any evidence of organ toxicity. Our present study illustrates a novel approach for the development of water-soluble "multifunctional agents", demonstrating efficacy for tumor imaging (MR and fluorescence) and phototherapy.