A luminescent nanoporous hybrid material based drug delivery system showing excellent theranostics potential for cancer

Article abstract of DOI:10.1039/c3cc43487g

A novel hybrid nanoporous material (LNH-1) bearing a tris(propyliminomethyl)-phloroglucinol fluorescent moiety in the framework has been designed and administration of an LNH-1 based drug delivery system containing doxorubicin to cancer cells showed inhibition of proliferation, suggesting its future potential theranostics application in cancer. This journal is The Royal Society of Chemistry.

Full text of DOI:10.1039/c3cc43487g

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A luminescent nanoporous hybrid material based
drug delivery system showing excellent theranostics
potential for cancer†
Cite this: Chem. Commun., 2013,
49, 7644
Received 10th May 2013,
Accepted 18th June 2013
a
b
Arindam Modak,z Ayan Kumar Barui,z Chitta Ranjan Patra*b and
Asim Bhaumik*a
DOI: 10.1039/c3cc43487g
www.rsc.org/chemcomm
A novel hybrid nanoporous material (LNH-1) bearing a tris(propyl- fluorophore tris(propyliminomethyl)-phloroglucinol (TPIM-P) moiety
iminomethyl)-phloroglucinol fluorescent moiety in the framework in the framework, which is synthesized through self-condensation of
has been designed and administration of an LNH-1 based drug 100% organosilane moiety under alkaline pH conditions. Due to the
delivery system containing doxorubicin to cancer cells showed presence of the strongly luminescent TPIM-P moiety inside the
inhibition of proliferation, suggesting its future potential therano- framework the material shows fluorescence properties in both lung
stics application in cancer.
and breast cancer cells, as observed using fluorescence microscopy.
The biocompatibility of LNH-1 materials to both non-cancerous
Surfactant-templated synthesis of periodic mesoporous organosilicas (HUVEC: human umbilical vein endothelial cells; CHO: Chinese
(PMOs) has attracted widespread attention for over a decade due to hamster ovarian cells) and cancerous (A549: lung carcinoma cells;
the possibility of grafting a reactive organic functionality in the MCF-7: breast cancer cells) cells was observed by cell viability assay.
framework of the nanohybrids, which could lead to many frontline Additionally, we have designed and fabricated a novel LNH-1 based
applications.1 Various bridging organic moieties (R) present in the drug delivery system (DDS) containing doxorubicin (DOX) (FDA
organosilica precursors [(OR0)3Si–R–Si(OR0)3] ranging from aliphatic approved drug) where LNH-1 acts as a delivery vehicle. The admin-
to aromatic and heterocyclic make them useful for advanced applica- istration of this LNH-1 based DDS to A549 and MCF-7 cells shows
tions, e.g. catalysis, gas and metal ion sensing, light harvesting, hole excellent therapeutic efficacy compared to free DOX.
transporting, molecular motors and so on.2 Although these meso-
TPIM-P has been synthesized from the Schiff base condensation
porous hybrid materials have been studied extensively, very little of 1,3,5-triformyl phloroglucinol (TFP) and 3-aminopropyltriethoxy-
research has been focused on template-free synthesis of organic– silane (APTES). 1,3,5-TFP was obtained through Duff formylation of
inorganic hybrid nanoporous organosilicas3 and their potential phloroglucinol and hexamine.8 The synthesis of LNH-1 is described
theranostics application especially in the treatment of cancer.4 More- in Scheme 1. All the materials and methods, synthesis of Schiff base
over, the high surface area and internal void space present in the
nanoporous material can make it an ideal medium as a drug delivery
vehicle5 and the luminescent framework in this material is highly
desirable for the development of fluorescent labels.6
In this context, nanotechnology can play a pivotal role in the
development of nanomaterials that can be used not only in cancer
diagnostics but also in cancer therapeutics and cardiovascular related
diseases.7 Herein, we report a template-free new organic–inorganic
luminescent nanoporous hybrid material (LNH-1) bearing an organic
a Department of Materials Science, Indian Association for the Cultivation of Science,
Jadavpur, Kolkata 700032, India. E-mail: msab@iacs.res.in;
Fax: +91 33 2473 2805; Tel: +91 33 2473 4971
b Biomaterials Group, CSIR-Indian Institute of Chemical Technology, Hyderabad,
500607, India. E-mail: crpatra@iict.res.in, patra.chitta@gmail.com;
Fax: +91-40-27160387/27160757; Tel: +91-40-27191480
† Electronic supplementary information (ESI) available: Characterization data of
the LNH-1 material and its use as a DDS, fluorescent label and in cancer therapy.
Scheme 1 (a) Schematic representation of the synthesis of LNH-1 and (b)
See DOI: 10.1039/c3cc43487g
structure of doxorubicin.
‡ Both the authors contributed equally.
c
7644 Chem. Commun., 2013, 49, 7644--7646
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Fig. 2 Biocompatibility of LNH-1 in (a) HUVEC, (b) CHO, (c) A549 cells, and (d)
cell-cycle analysis of A549 cells treated with LNH-1 (100–200 mg mLꢀ1).
Fig. 1 13C (A) and 29Si (B) MAS NMR spectra, (C) photoluminescence spectrum
and (D) TEM image of LNH-1.
average pore diameter was found to be 0.899 cc gꢀ1 and 4.5 nm
respectively.
and LNH-1, conjugation of LNH-1 with DOX and their detailed
The cytotoxicity assay of new kind of materials for any cell is the
characterization along with several in vitro assays9,10 are described basic and preliminary criteria for biomedical application. Therefore,
in detail in the ESI.†
in order to investigate the cytotoxicity level of LNH-1, MTT assay was
13C and 29Si MAS NMR spectra of LNH-1 are shown in Fig. 1A carried out for both non-cancerous (HUVEC: Fig. 2a; CHO: Fig. 2b)
and B, respectively. The 13C spectrum exhibits several peaks at 8.3, and cancerous (A549: Fig. 2c; MCF-7: Fig. S6, ESI†) cells. Results
23.3, 51, 103, 158, 183 ppm corresponding to the alkyl groups of show that the LNH-1 material is highly viable up to 200 mg mLꢀ1 for
APTES, the quaternary carbon of the phenyl ring attached to the both normal and cancer cells. The biocompatibility of LNH-1 has
imine CHQN– group, the phenyl ring carbon attached to the –OH further been supported by the cell cycle analysis (Fig. 2d) in A549
group and the imine carbon of the Schiff base. These 13C signals cells treated with the LNH-1 material where the G2/M phase
suggest the presence of the TPIM-P moiety in LNH-1 and 29Si NMR decreases in a dose dependent fashion indicating that this material
exhibits a weak downfield chemical shift at ꢀ60 ppm and a very is not cytotoxic toward A549 cells. So, the LNH-1 material can be
strong and sharp peak at ꢀ68.5 ppm, which could be assigned to T2 used as a drug delivery vehicle as it is biocompatible in nature.
and T3 species.11 Presence of the T state clearly signifies the Therefore, we have designed a LNH-1 based DDS containing the
complete hydrolysis of the organosilane moiety and absence of anticancer drug doxorubicin (LNH-DOX). Comparing the TGA ana-
any Q states (Q1–Q4) ruled out any possibility of the breaking of Si–C lyses of LNH-1 (Fig. S7a, ESI†) and LNH-DOX (Fig. S7b, ESI†), we
bonds, suggesting the direct incorporation of the TPIM-P moiety in have found that 5.9 wt% binding of DOX in LNH-DOX corresponds
LNH-1. This finding clearly demonstrates the hybrid framework. to 1.4 ꢁ 1015 DOX molecules per mg of LNH-DOX powder. Again, in
The photoluminescence spectrum of LNH-1 (Fig. 1C) in the solid CHN elemental analysis, 2.51% of C, 0.32% of H and 0.74% of N are
state at room temperature exhibits a strong red emission band at increased in LNH-DOX from LNH-1, indicating the binding of DOX.
595 nm upon excitation at 465 nm corresponding to the presence of The exact bonding nature of DOX to LNH-1 is unknown at this
the organic fluorophore moiety. In Fig. S1 (ESI†) the powder X-ray moment and needs further investigation, which is beyond the scope
diffraction pattern has been shown where in addition to a strong of our present study. However, it may be electrostatic, covalent,
sharp peak in the low 2y region (2y = 5.96, d = 1.53 nm), a weak peak co-ordinate, H-bonding or a combination of them. DLS study shows
at 10.6 (d = 0.86 nm) has been observed. This diffraction pattern that all the zeta potential values of LNH-1, DOX and LNH-DOX are
indicates a new class of porous architecture of LNH-1. The TEM positive (5.1 mV, 12.5 mV and 16.9 mV respectively) (Table S1, ESI†),
analysis reveals that LNH-1 is composed of self-assembled hollow indicating the absence of any electrostatic interaction between
nanoparticles of dimensions ca. 100–150 nm (Fig. 1D). Fig. S2 (ESI†) LNH-1 and DOX. According to the earlier literature12–15 we can
shows the high magnification TEM image of the marked part of speculate that the nature of bonding may be covalent, co-ordinate, or
Fig. 1D. CHN analysis of LNH-1 revealed the presence of C: 36.6%, H-bonding as DOX molecules contain –OH, –NH2 and QCQO
H: 5.12%, N: 7.07%, and FTIR (Fig. S3, ESI†) and UV-vis spectro- functional groups and LNH-1 contains –OH, and –NQ functional
scopic (Fig. S4, ESI†) analyses further suggested the presence of a groups.12,16,17 Whatever, the weight loss in the TGA profile (Fig. S7a
fluorophore moiety in LNH-1. The N2 adsorption–desorption iso- and b, ESI†) indicates the bonding of DOX to LNH-1. 13C CPMAS
therm of LNH-1 (Fig. S5, ESI†) suggested microporosity and its BET NMR of LNH-1 and LNH-DOX further supports the bonding inter-
surface area was found to be 175 m2 gꢀ1. Furthermore, substantial action between LNH-1 and DOX (Fig. S8, ESI†). The release kinetics
entanglement at very high pressure with low hysteresis indicates study of DOX (Fig. 3a) from LNH-DOX shows the slow release of
intermolecular mesoporosity in LNH-1. The pore volume and the DOX in DPBS buffer indicating the stability of the nanoconjugate,
c
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LNH-1 in A549 cells (Fig. S13, ESI†) whereas non-cancerous CHO
cells (Fig. S14, ESI†) show very little fluorescence. The results indicate
that cells treated with LNH-1 show a higher transfection efficiency of
LNH-1 towards cancer cells rather than towards normal cells. Finally
these results indirectly prove that the LNH-1 based drug delivery
system can selectively target cancerous cells.
In summary, the new luminescent nanoporous hybrid material
LNH-1 reported herein is biocompatible and administration of the
LNH-1 based DDS containing DOX shows significant inhibition of
proliferation in lung and breast cancer cells compared to free DOX.
Additionally, in vitro fluorescence properties of LNH-1 suggest that this
technique might be used for in vitro imaging. The results altogether
indirectly indicate that the LNH-1 based drug delivery system can
selectively target cancerous cells compared to normal cells and the
DDS can be useful for future theranostics application in cancer.
This work was supported by DST Unit on Nanoscience (AB),
Ramanujan Fellowship (SR/S2/RJN-04/2010), DST, New Delhi to
(CRP) and CSIR (CSC0302), New Delhi. AM and AKB are thankful to
CSIR and UGC, New Delhi, respectively, for their research fellowships.
Fig. 3 (a) In vitro release kinetics of DOX loaded with LNH-1 materials. (b) The
application of LNH-1 as a delivery vehicle in A549 cells where the anticancer drug
DOX was attached to LNH-1.
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7646 Chem. Commun., 2013, 49, 7644--7646
This journal is The Royal Society of Chemistry 2013